a little unknown object - M45 revisited after 2 years

[Konihlav]

Dear ASA friends,

here's a 66% size result from 3 hours of shooting (12x6min + 6x6min RGB) with my ASA 10" and G3-11000 CCD:


the 100% size link is just below the image, above technical data, ready to click.

Pavel
 

 

 

[afesan]

Hi Pavell.

 Fantastic image... A gem ¡¡              .. Just a little appreciation of a problem into the upper-center-left side of sensor with stars out of focus with respect to the image. Spikes and star sizes are different--- so it seems to me there is a little problem of distances in the optical train...?..

 

Colour, procesing and details. overall...are great ¡- 

Congrats¡

Antonio

[Konihlav]

Hola Antonio, claro q si y q lo se...

 

sure I know it, it's always something. I got used to the "3 corners rule" that says - 3 corners are OK, one is tilted. It is better in G and B and worse in R and Luminance. Anyway I just decided I would crop 100-200 pixels and be OK. I know my both hands are left ones when it comes down to "collimation". The problem with catseye's infinity is that it is soooo precise that you are always a bit off next time I plan to use smaller sensor of Atik ONE for narrow band imaging but that small pixels are also hard to deal with as they show some other problem (maybe overtightened mirror even though I try just to hand-tight it). With changing temperature of the mirror everything is on the move so it is really difficult to "manage it" for a 1:1 full scale image. In 50% size everything looks good, but I am on the chase of resulution...

 

thanks!

Pavel

[GeorgeCarey]

You two must have good eyesight. I can't see the effect you are talking about.

[rbrecher]

Very nice.  Amazing how much detail you are able to pull from a relatively brief integration time.  I think it's time for me to to image this again.

[Waldemar]

Hi Pavel,

 

I also think this is a beautiful picture of the Seven Sisters, but Antonio is right, there are quite some elongated stars in the picture.

Not only in the left top, but the whole top half and left side. The 3 corners rule is kind of inverted: 3 notsogoodcorners, 1 good: The right bottom side...

I think this can only be caused by a tilted camera, due to a hanging focuser, a flaw in the imaging train or a not so well mounted sensor, which is unlikely for a Moravian camera. The problem is easily solved with a CTU:

 

http://www.gerdneumann.net/english/astrofotografie-parts-astrophotography/ctu-camera-tilting-unit.html 

 

Maybe this is the solution you were looking for?

 

Best regards,

Waldemar

[GeorgeCarey]

CCD Inspector shows a small tilt. The field looks nice and flat.

 

 

 

[Konihlav]

Waldemar et. all:

 

could YOU PLEASE post somewhere any raw fits (or converted to JPG) field in full size to show how good is your imaging train and telescope collimated???

THANK you.

 

I know the issue I am looking for a solution and I cannot find it.

My best test-frame was this:

http://www.astro.cz/galerie/d/61075-1/CCD+Image+50-highscreenstretch.jpg

 

but since that time I did not manage to make the collimation so good since then.

 

I am a ghost-chase, I am the most top-demanding guy here I am sure, but I really like you others to show similar full size frame from your big chip camera. For me, every pixel counts and am unfortunate when I have to downsize to 50%, but that's the only way now to get around...

 

thanks!

 

BTW my experience says that anything "made by g. neumann" is not good (piece of garbage), I had few things and I never make the same mistake again.

[Waldemar]

I am sorry to hear about your bad Neumann experience Pavel.

I only have a TEC140, which can not be collimated, and my biggest sensor is APS size, so I am in a total different league than you.

Not comparable...

That test-frame is quite perfect I would say... I can only see perfectly round stars, even in the most outer parts of the image...

 

Waldemar