Konihlav

I have found the problem - it is the primary mirror, the outer edge... I will describe it in detail in yet another blog article when I get some time to do so...

yes, Matts, but still I'd prefer if there is no Moon at all even for H-alpha imaging :-)

George, looking forward to hear from you back your personal experience (most valuable thing). One friend of mine uses the one from TS and doesn't have it perfectly in-line and other friend just broke the carbon spider when he tightened the screws so he replaced with custom made single piece spider that partially causes square shaped stars if the ratio between thickness of the vanes versus scope front aperture is not in favor...

end of the story: http://blog.astrofotky.cz/pavelpech/?p=958

Hi all, finally, after years of wanting to do so, I did it:

Hi Thomas, am I right when I guess, that you were inspired by my first-light image (that ASA also presented on facebook month(s) back) http://astrofotky.cz/gallery.php?show=Konihlav/1374349498.jpg ??? :-) after my LBN603 attempt (having only 90min total integration time) other 3 guys from Czech Rep. were imaging this not known target too so there are now "many" LBN603s best regards and CS Pavel BTW your image looks cool, mine is a bit over saturated (but I love colors) and missing L-channel data

Hi Thomas, thank you! let's say, I'm satisfied with the image in spite of the few issues - that meriflip issue is a mystery to me, but I let you know when I resolve it... (so far I decided to just image on one side of the meridian). thanks Pavel

so far, I can rule out (for 100%) that it is NOT a tube current - last night I tested imaging with mirror fan ON and OFF etc. and no difference. I still have 2 things to check left. I come back to inform you on my next findings...

Hi there, I've had this object on my TODO shoot list for more than two years... finally I got a chance to take few subs of it. Unfortunately I had a problem with meridian flip causing rotation of the tube and therefore misalignment of the diffraction spikes (see http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/?g2_page=4 for more information if interested). here's the resulting image: it's 5.5hrs total (6min subs). It would be great if I could add some H-a data for the H-a stripe, but the weather doesn't allow so I have to limit my activity. Good I have F/3.6 now thanks for any insights/comments CS Pavel

yes, I can confirm that my secondary mirror does have the whole side painted WHITE (or white/transparent) instead of black as George shows on the image above. Therefore, next time out (could take a month or two in our damn bad weather conditions) I will: - check tube current - introduce central obstruction to eliminate white edge problem of secondary mirror - remove OAG prism (though I doubt this is the case, but for sure I need to systematically do all stuff proposed) - capture some video of defocused stars in all color channels in order to do roddier analysis... I let you know when I get more data...

Dear Wolfgang and George, thank you very much for your insight, I really appreciate it. Wolfgang - that was one of the questions I sent to ASA prior my N-10" purchase :-) I asked on edges of secondary if they are blackened or not (because in the past, few years back, I read on yahoo group of someone having issues shooting flat field frames and also from my friends that build their own Newtonians that it is a good idea to black it). Do you think oversized like more oversized than the 100mm dia that is in my 10"-ASA ? Could I try just to put some obstruction on the secondary (on top of it, like cut bigger circle aperture blocking light around secondary - increase central obstruction) ? the tube current idea is also very nice (confident) - I try to turn off the primary mirror ventilator next time to see if there's any change... George - problem is I have limited space in my office, I have no big laboratory to make these experiments. Also both my hands are left-hands so I have rather went with ASA then any DIY so any rotation of primary mirror is out of question as I do not want to screw things... but it is certainly a good idea for identifying which mirror is on blame (provided all else is OK). Anyway I very much hope both mirrors are fine, only the secondary one has "white" edges. I try to make some central obstruction and see if it has effect or not. thanks anyway! BTW the winroddier home page is here: http://www.astrosurf.com/tests/roddier/projet.html in the meantime I purchased a planetary (video) camera in order to capture the airy patterns a better way...

Hi George, defect in any camera is out of way as I have two cameras and both show it. yes, it is possible to rotate both: 1. either only the Wynne corrector (by using different thickness spacers - I have a set of 0.66mm 1mm and 1.33mm to fine tune the backfocus distance) - therefore every time I change the spacer (already tested none, 0.66mm one and 1mm which make resultant focal length of some 906.something, 904.1mm or 903.4mm respectively). when I put different spacer I have effectively rotated connection Wynne+CCD 2. rotate Wynne inside of the focuser tube (for composition orientation) results in different camera position (angle) for astroimaging composition. I have found two examples from two nights where I have this changed in my setup, once I was shooting vdb152 Luminance (I stupid uploaded NGC7129 from different night, but the orientation of camera was more or less (by 5-10 degrees) the same I am sure about it): http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/session-2013-09-06.jpg.html Pos Angle +272° 05', FL 903.4 mm (using 1mm spacer results in 903.4mm BFD) here star pattern: http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/NGC7129-Luminance-FL-W5.jpg.html another night vdb152 RGB colors (ignore the alignment/rotation problem in red channel) and star pattern: http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/phuckstar.jpg.html OTHER night and OTHER rotation of camera, shooting LBN603 in July: http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/session-2013-07-15.jpg.html Pos Angle +345° 58', FL 904.1 mm (using 0.66mm spacer) and voila - different orientation of the defect http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/LBN603-W6luminance.tif.html so what does it say??? when I get the chance to go out and shoot the stars, I remove the OAG prism with one of the small hex keys and see if the pattern disappears or not though I doubt it is OAG now :-( I was very much hoping the problem won't be in mirrors. Any other possibility??? What do you say George, others???

Hi George, I have just checked the data I took few months back when I tried the WinRoddier analysis (computed Strehl of 0.00something instead of 0.8 or 0.9something due to badly acquired data). Here's what I found: 1. the "defect" doesnt stay at the same o'clock position - when I change focus postion (inward to outward or vice versa) it moves to the opposite side of circle (e.g. from 5 to 11 o'clock) 2. it was probably big coincidence that both cameras had same length threads so that screwed in resulted in same camera angle orientation within the focuser tube 3. because - I found that one day I rotated the camera (fixed on 3" Wynne reducer/corrector) about 90 degrees different way and the "defect" moved from 5 o'clock to 8 o'clock position... (i) I was suspecting problem with either primary mirror or secondary mirror - maybe due to my unablity (not enough skill) of collimation and because I have always bad luck with new equipment so I am used to find problems where they do not exist (ii) at the moment I realized I do have OAG prism in there. But can't understand that also tiny chip of 16mm diagonal (Atik 460) can show this defect (while I would expect big 36x24mm chip to show it which would be OK with me). but why the small chip shows that too is a mystery for me at the moment...

Hi all, does anyone have a clue what can cause "this" extra/weird diffraction - see red arrow in detail here: http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/strike.png.html full scale - http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/M45TEST.jpg.html?g2_imageViewsIndex=1 can it be related to airy disc pattern? looks to me like on both images it's at about 5 o'clock possition: http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/strikediffraction.png.html?g2_imageViewsIndex=1 full scale - http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/m45-018L.jpg.html?g2_imageViewsIndex=1 both taken at the same time (in the morning, mirror was cooled down/stabilized after 5+ hours). what is more interesting is that I have the same "weird"/extra diffraction on all my LRGB images even those taken with differnet CCD camera (the image above is done with Atik460EXM - small chip - while the one below is done with G3-11000 using KAI-11000 full frame chip) on different nights/sessions... e.g.: http://astrofotky.cz/gallery.php?show=Konihlav/1375952959.jpg once, I wanted to do a roddier analysis of the mirror, but as my first attempt I didn't gather quality data (missing video camera). Next time I hope I get more relevant data. But anyway, in the meantime, I'd like to hear few comments/ideas. thank you all for publishing your opinion Pavel BTW it is done with 10" N-ASA (mirror is glued, no holding brackets visible at all), there's nothing in the light path.

here we go, HST palette: 66%size: 100% size: http://www.astro.cz/galerie/d/62204-1/Pacman_HST_001.jpg

thank you Antonio, I just processed a bicolor version (haven't done bicolor processing for years), here's my quick output: HST will follow, one day...

cool image, Antonio, una vez quisiera también tener un observatorio (en un lugar adecuado), quizás...

Hi Stuart, since you got no response, I went ahead and measured current draw of my system (ASA N-10" with standard OK3 OAZ/Focuser). Here are my findings: 13.91V input voltage 5 watt power supply only consumption 8 watt with primary mirror fan on focuser consumption 7 watt idle 17 watt when moving at full speed (U = 13,90 Volt) I = P / U 2 / 13.9 = 144mA 3 / 13.9 = 215mA 5 / 13.9 = 360mA 7 / 13.9 = 504mA 8 / 13.9 = 576mA 17 / 13.9 = 1.223 A therefore I'd say the primary mirror fan takes from 200-300 mA while the OK3 takes at most 1.5A peak when running and about 0.5A when "idle". This means, that for my mobile setup I can calculate with < 1A per ASA telescope (OK3 + fan). sincerely Pavel

Ian, I own both most popular tools, i.e. the catseye set (Infinity XLK + Blackcat XL) as well as Howie Glatter's tools (along with tuBlug and some other tool for secondary adjustment)... both tools have some weak points that piss me off very much (I am very demanding customer who hates any weak points ever). As MarkS (above) points out, it's essential to not tighten any of the screws, rather to make sure you strongly fit the front side of the collimating tool to the 2" sleeve. I hate this approach, but all the manufacturers are just idiots... strong points of Howie Glatter's tools: + using tuBlug (essential thing) you prevent the common tilt (wobbling) issue in the sleeve holder! + tuBlug also allows you to collimate from the back end of the OTA and just watch the pattern from behind as usually done with common lasers that visualists use weak points of Howie Glatter's tools: - since it is a laser, it itself needs to be collimated well in the factory (a random point, if you are unlucky man like me...) - in overall the laser is lot less precise than Catseye! strong points of Catseye tools: + it is very precise (precise-most) tool which in the end renders a weak point: weak points of Catseye tools: - due to high precision, it always shows me some residual error - I never saw my pattern 100% perfect (using triangles) there's still some error left and I have two sets of both tools (my and my friends one) - doesn't fix the common wobbling issue like tuBlug (why don't the "idiots" make tools for screwed attachments for us photographers - that would rule out all wobbling/tilt issues and only tilt in camera sensor would be left - I know why, because only 1% of people (like me and few others) are able to detect this stupidity the rest 99% downsize images to 50% and seems to be happy with it) - using it with bigger then 10" size Newtonian is a problem with ASA as collimating ASA with two different hex keys from behind is VERY uncomfortable (you can't look directly into the infinity and at the same time play with the stupid hex keys...) a man would like to have some webcam looking into the infinity (problem to look into both holes, central and offset) on the other side - when you finish the hard to do collimation of ASA, the ASA is really WELL built and HOLDs collimation!!! this is most important. anyway, the best (random luck) of Newtonian collimation was this: http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/CCD+Image+50-highscreenstretch.jpg.html?g2_imageViewsIndex=1 but since I let ASA to fix the non-parallel problem with my secondary vane (spider holder) - so now I have much better spikes from bright stars - I did not manage to collimate well and reproduce the unbelievable "luck" demonstrated on the image above... all best Pavel

Hi there, again, this is "just a try", I had some slight issues with tracking as I haven't done hi-res imaging for a looong time. Hope next time I get even better result and hope the weather allows for capture of some SII and OIII data to make a HST image 66% size: link to 100% size can be found right below the image in the gallery window. Pavel BTW done with Wynne 3" that I use for full frame camera. I'd like to get the ASA's 1.8x barlow or Quattro (x1.175) for this small Atik, but missing $$$ and here's the setup in the field (I am a mobile photographer):

Hi there, finally, after long time I managed to capture some data with my new ASA 10" Newtonian at F/3.6 using Wynne and 36x24mm CCD. This is my 3rd light image, first that I am not afraid to show to the public. even though I still have some tiny problem with either collimation, tilt or backfocus :-) the mixed color space image (RGB composition) hides it (mono is worse to show in full size). Anyway, for those who wonder how 1:1 image looks like (at 100% only slight corner crop as my setup works perfectly only in 90% of the FOV) here's the full size image: http://www.astro.cz/galerie/v/uzivatele/Konihlav/big/NGC7129-ALL2gether-W9final.jpg.html?g2_imageViewsIndex=1 hope you like it, best regards Pavel

Hi Ralph, here is the answer (I hope): http://blog.astrofotky.cz/pavelpech/?p=207 and http://blog.astrofotky.cz/pavelpech/?p=299 personally, I own only one 5nm filter now as I already sold all other 5nm filters I ever had due to an upgrade for 3nm set I would always recommend 3nm OIII, 3nm SII and based on your budget decide between 3nm or 5nm Ha (I own both 3nm Ha and 5nm Ha as the 5nm one also covers the NII line found in few planetary nebulas). do not worry about mixing different bandwidths (unless the difference is too big like 35nm and 5nm filter) it's all question of post processing where you can do wonders (if some filter produces bigger stars then the other one, you can deal with everything in Photoshop). For NB imaging I own a CCD camera with ultra low readout noise. For HaLRGB imaging I own a large format low sensitivity high noise camera because LRGB imaging is far different from NB. hope this helps Pavel BTW the fastest system I use is F/3.6. For F/2.8 I would think of 5nm filters for "safety" (Ha and SII, keeping the OIII at 3nm)

Bob, the problem is not that dimm stars have small diffraction spikes and bright have large spikes, that's obviously pretty normal. The problem is that the diffraction spike diverges from single line (near the bright star center) into two lines with increased distance proportional to distance from the focused bright star center. That shows the double spider vans to be not parallel (in-line) with each other, I am pretty sure about it. Anyway, here are new data I collected this weekend (6th clear sky night this year!!!), I learned many new things: First of all I spent almost 2 hours collimating the telescope using both CatsEye toolset and Howie toolset. Then in the night I tested: - focus in center - focus in corner - rotate camera - ... bla bla - increased backfocus using a rubber band that I inserted between camera adapter and my CCD camera (resulting focal length seems to be closer to what it should be) - with this new config I well focused and voila, great star field images (except of the damn stupid double which should not be present!) here is a sample of ordinary green output: http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/NewBFD_Focused_Green.jpg.html BTW Plná velikost MEANS full size and další MEANS next here is a sample of superb luminance output: http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/NewBFD_Focused_Luminance.jpg.html?g2_imageViewsIndex=1 here is flat field in CCDInspector: http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/NewBFD-FlatAnalysis.jpg.html?g2_imageViewsIndex=1 vignetting in MAxDL: http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/NewBFD-FlatMaxIm.jpg.html?g2_imageViewsIndex=1 AND FINALLY the star field image: http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/CCD+Image+50-highscreenstretch.jpg.html?g2_imageViewsIndex=1 so now, EVERYTHING is perfect EXCEPT of the star spikes. I am in contact with ASA guys already, will let you know when I (we, they) resolve this issue. Pavel

thank you guys for now, I asked ASA on their opinion... gmalits - I have checked the collimation now (if it lasts after driving 220km) and it is "almost" OK checked with tuBlug Howie Laser. Using infinity is not easy as I can't do both tasks - look into the infinity and use the hex allen keys to turn the collimation screws... and the infinity doesn't fit the 2" clamp very well - there's (big enough) wobble making a use of precise infinity useless. what I may be able to check next time is the backfocal distance (though we precisely calculated I need camera adapter of some 21.79mm which ASA produced for me because I got OAG from ASA too). I may be able to increase BFD next time by a 1mm and see. I may also try to focus in mid/half position from center of the image to the image edge (this pre-zero light (test) ) was done with precise focus, but in the middle of the field... I may also try to capture diffraction rings of a defocused star (though the secondary offset should make the circles not being round at this fast F/3.6 speed). at the moment I am still "convinced" the problem is in spider vanes being not in-line. I keep you informed on my next findings. Pavel

Yes George, it's unfortunately really apparent I will have to contact ASA about it. Here's a quick test of uncalibrated 1x3min RGB bin2x2: http://www.astro.cz/galerie/v/uzivatele/Konihlav/misc/usa-001-RGBtest1x6min_nocalib.jpg.html?g2_imageViewsIndex=1