MarkS

Both galaxies are pretty interesting!. They are totally inaccessible from here (southern Australia), so its nice to see such a good shot of them! Mark

This fairly faint nebula is very disturbed - a major contributor to the 'windblown' appearance of it is a Wolf-Rayert star near its centre. This image was taken from my backyard in suburban Melbourne (SQ-L reading 18.3). I posted a version previously on the Facebook page, but I like this slightly modified HCP version better. ASA10N at f/6.8; STT8300 camera; DDM60; Astrodon 5nm filters; 10min subs in Ha, SII, OIII; total exposure 5 hours.

Hi Bernard, I use a laptop - my set-up is mobile so I have to set up from scratch every time anyway. I don't think there is a power issue because the hub, which only connects the receiver and the OK3 focusser, is in a USB3 port. Regards, Mark

Yes, I routinely use a Logitech Wireless F710 With my set-up, the turn-on sequence matters - I don't know why. I do not plug the wireless receiver into the USB hub until Autoslew and the mount are on. Then I plug in the receiver, and hit the start button on the gamepad. A green light flashes and then goes out. Then I start the DDM motors, click on the gamepad icon in Autoslew. The cross disappears, and everything works. This sounds messy, but it's not - just part of my start-up routine.... Hope this helps. Regards, Mark

I've been off the air for a few days,so I've just seen this. I gave up on the CGEM tripod - I couldn't stop it vibrating with any reasonable PID settings! Regards, Mark

Usually that is a sign that the tuning is too hard. Try backing off the PID numbers a little and see if that helps. Regards, Mark

Hi Tim, Does AS report a "Position Error" when the DDM85 freezes? If not, ignore the following If so, it may be worth putting an ammeter in the DDM power supply lead to track the motor current. With my DDM60 it will always show increasing current when a position error is imminent. I have found the only infallible way to optimise Balance is to minimise motor current over long tracking times. I always set up with the Balance Tool, but it doesn't always guarantee trouble free running over long periods. Also, when I use Sequence Run to set up a long session, I always program a relaxation slew and re-focus every hour or so, which 'resets' the motor currents to low values. It's just a precaution but I find it is good insurance against problems if I haven't nailed the balance - which I have to re-establish every session on my mobile set-up. Regards, Mark

Markus, this is very strange indeed. Have you tried returning Autoslew to factory settings, and then setting up all the parameters again from the beginning? Regards, Mark

Hi Markus, Could the polar alignment have shifted? What is the PA error? Mark

Hi Ron, I'm using a Farpoint shield made to fit the 11" Celestron (easier to get than the Celestron). The shield projects about 300mm forward of the ASA10 front. I take my flats with a light box source that the shield faces onto. These flats seem to work fine. Regards, Mark

Following Luke's crit of the original image, I have revisited the data, and added an L channel 'manufactured' from the R data. The process was a little involed, and I'm not sure if it is the best that can be done, so maybe this is a work in progress!

Thanks Luke, I have thought about that - and I will revisit the data. I guess I'm currently a little besotted by the power of the f/3.6 scope ! Mark

Hi again Dave, Once the DDM is polar aligned - and to do this accurately you do need the camera - changing to eyepiece only requires rebalancing. Then I would just use TheSkyX to send the scope to wherever I want. (However, I tend not to to visuals with my ASA10N because a fast scope like this is not ideal for observing bright objects. For observing I like to use a APO refractor.) The caveat here is that balance for photography is very critical, so it can take a while to optimise even if you have good starting marks on the equipment. Regarding software etc, I use Windows 7 64 bit, but I am told there is no problem with Windows 8. What the future brings is anyone's guess! Mark

Hi Dave, I am in the Southern Hemisphere, so I don't have Polaris to work with. I use a digital inclinometer with accuracy of +/- 0.2 degree or better to set the tripod level. At my favourite sites I have measured True South by the Sun at local noon. This is used to set Azimuth with the aid of a sighting tool placed on the DDM60 base. The inclinometer is again used to set the OTA altitude to the latitude. Balance is optimised with the Balance Tool in Autoslew. So far, I have tuned the system once, and repeatedly used the settings without rechecking. I use the 3 star routine in Sequence for Polar Alignment. Two iterations are sometimes necessary. When PA is within 1-2 arcmin, I either do a 21 star configuration and then MLPT, or just go straight to MLPT in Sequence. Both options have always given perfectly satisfactory tracking for 5 - 15 min subs. My total set-up time including assembling the whole system is usually less than 1 hour - I do need to assemble in daylight for the Azimuth alignment. Mark

This one was shot on 26 January. Not a tough target, but not one I've seen much. RGB; 2 hours total using the ASA10N at f/3.6. SBIG STT8300 mono; Astrodon filters DDM60 using the beta software. It was quite a windy night - interesting watching the motor currents! Processed in Pixinsight and Photoshop.

Following up on this, I have experienced some horrendous dew conditions this summer near the coast - ~100%RH at a temperature of 25C. The fan running flat out plus a Celestron 11" dew hood has kept the condensation at bay! And 5min subs look fine. Mark

Hi Ian, Glad to hear it was OK - it's an easy trap. A 'long distance away' ain't infinity! With the 57 mm stand-off the focus point using the Pentax eyepieces was within a mm or so of the photo focus point, which seemed fine. Regards, Mark

My mobile DDM60 set-up will run all night on a 38AH battery, so it's not an issue for me! Mark

I always use the same temperature - minus 25C - so it is only the time that scales. I haven't yet done a direct comparison, but I have used the scaling on narrow band sub calibration. It seems to be fine. If I get a chance in the near future to do a direct comparison I'll post the result. Regards, Mark

PS: If you are using Pixinsight for calibrating your images you do not really need different Dark exposure times: Pixinsight will scale the Master as needed - but it does need to have minimum noise. Mark

Hi Michael, I can't answer the question on the camera on-time. I suggest you ask SBIG - they are usually prompt with their replies. I have settled on 25 subs for Master Bias, Dark, and Flats Most of my deep sky exposures are in the range 5-20min. with the ASA10N scope. 25 seemed a reasonable compromise to me - given that one is doing multiple subs to minimise noise in the Masters. 25 subs give 1/5 the noise of one; to get twice as quiet would need 100 - too many for me! Regards, Mark

I strongly agree with Ian on this. The wiki may well serve as a valuable complement to up-to-date comprehensive manuals, but in no way can replace them. The production of a new set of manuals is a major undertaking, made more difficult by the rapid rate of development, particularly the software. Is it feasible for the Autoslew and Sequence manuals to be overseen and edited by ASA, rather than writing them completely? Some of the beta testers must be pretty familiar by now with the software, and perhaps could contribute to sections of the manuals defined by ASA, and then edited by ASA . This could spread the task, and improve the ability to keep the manuals current. Related to this is the language issue. For example, some of the English in the current manuals is a little confusing. Surely this is something that some of our users could assist with. It is obviously essential that ASA retains absolute control of the output, but there is likely to be a number of us users who have the technical and writing abilities to contribute. The ASA products themselves are incomparable, so I do not make these comments as criticisms, but rather to explore practical options for keeping the manuals current in a fast developing technology in which all users have a strong investment and interest. Mark

Hi Matts, I have not tried anything yet, as the really bad experience I had happened only two nights ago. Prior to this running the fan on full had been enough. Your reply is most encouraging, and I will try the shield - I would far rather do this than introduce heaters and wires etc! Regards, Mark

Has anyone fitted secondary mirror heating to an ASA 10N? I've suddenly become interested following the partial ruin of an otherwise excellent photography session by uncontrollable dew formation on the secondary mirror. Are there any reasons why fitting a heater should NOT be attempted? If there aren't, what suitable units are there on the market? As one of my prime dark sky sites is particularly susceptible to dew formation around this time of year, I eagerly await help on this issue! Mark

Hi Nigel, Since no-one has offered any suggestions, have a look at the manuals for the N series Astrographs. There they identify the pull and push screws. The pull screw is the middle one in each group of three, flanked by a push screw on each side. And there is a bit about collimation, though the English language instructions are not all that clear. Whether this is relevant, I have no way of knowing. Your description matches what my N10 looks like. Your main cell may well be similar in basic construction - except the mirror won't be glued to the frame, I guess. Hope this might help a little! Regards, Mark