Altair Astro starwave 102 f7 for deep sky

[Frank Filskow]

Hi I've been getting to grips with my starwave 102ED and have had some success with my Nikon 5200 on the moon and andromeda. Struggling with smaller fainter objects. Just got the 2xbarlow to try that out. Has any body got deep sky pictures with the same scope they could share so I can see what kind of setup and techniques your using for the results your getting?

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[michael.h.f.wilkinson]

I haven't got such a scope, but I wouldn't go after fainter targets with a Barlow. This quadruples the required exposure time.

[Frank Filskow]

Thank - I was trying to capture the whirlpool galaxy but it was so tiny. My FOV with the Nikon / scope only is about 2degrees which I suspect is right for the nebulae but very big for a lot of other subjects. I tried taking a picture of the lagoon nebula by attaching the camera to the eyepiece at 8 mm but that was heavily distorted because the field wasn't flat can you give me some pointers?

[johnrt]

You simply need a scope with a longer focal length & more aperture to maintain a reasonable focal ratio, the 715mm of your scope is too short for the vast majority of galaxies.

Adding the Barlow will make your scope f/14 which is way too slow for deep sky imaging.

Have a play with this tool to see what different fov's scopes offer on targets like M51

http://www.12dstring.me.uk/fov.htm

[Frank Filskow]

Hmm. Not sure I'm ready to splash out on another scope yet. I was thinking the Barlow might help bring medium sized object full frame like m42 - do you think that will be too dim? I presumed I could increase he exposure time from 30secs up to a 5 minutes for each frame?

[Uranium235]

Trying to fill the frame with your targert is a common error, dont fall into that trap... no need for a barlow.

For instance, image something like M42 - then zoom in to 100% scale. At 715mm it should almost fill your montor (depending on its size) - which is big enough! Also, the barlow will introduce coma and all sorts of nasties into the image, theyre really not designed for DSO imaging.

Its not wasted though, you can use it for Lunar or planetary imaging/observing.

[fwm891]

Your Starwave and camera are fine - forget the barlow for photographic work of DSO's (though you could use it for planetary images as they're so bright). M51 and other DSO's will photograph well with your scope/camera you need to gather lots of sub frames and bring them together in something like Deep Sky Stacker. There are loads of tutorials on the web - even within DSS.

Your main problem I expect is the processing of the images you have taken, Astronomy Now have been running articles on various processing procedures - beg, borrow or even buy some back copies.

[Frank Filskow]

Have a play with this tool to see what different fov's scopes offer on targets like M51

http://www.12dstring.me.uk/fov.htm

Thank you for the link - great tool and illuminating. Do I've got plenty of larger DSO objects to go after first:

Large!

M7

M8

M31

M33

M39

M42

M45

Medium

M16

M17

M20

M78

M81

Now all we need is for the skies to clear...

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[Frank Filskow]

Trying to fill the frame with your targert is a common error, dont fall into that trap... no need for a barlow.

.

Thank you for your advise - I'll press on without my Barlow. I've bought a new intervalometer because the Nikon built in one has a maximum exposure of 30secs because rather than ISO6400 I'm presuming that 4-5mins at a lower ISO will allow the faint detail to burn in?

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[ollypenrice]

Your guiding and the darkness of you site are the main factors in deciding on sub length. The build up of thermal noise in the camera is another. But exposures should almost always be as long as these factors will allow. WIth cooled CCD I go for 10, 15 or 30 minutes depending on filters and targets. I've taken a few images with this scope and, although it isn't fast, I think it gives very good results. This was the Snake, which is always low from our site and it's faint, being a dark nebula. Even so, F7 didn't do a bad job of it in my book.

https://ollypenrice.smugmug.com/Other/Nebulae-and-clusters/i-tKG6dgH/0/X3/B72%20SNAKE%20ALTAIR%20TRIPLET%20102WEB-X3.jpg

Olly