is the c8 too strong for dso

[iwols]

hi all after one of those bad nights you get even though conditions were very good,does anyone think a c8 is too powerful for dso,with a nikon d750 attached,also what is in the sky tonight that would be worth a visit and a good starting point thanks from a dismayed starter

[psamathe]

2 hours ago, iwols said:

... thanks from a dismayed starter

Addressing your final point (and as a beginner myself), never get dismayed.  The time to get dismayed is when you are an expert and the image you've spend all night every night for the last week collecting and then days processing is then turned down for publication as its not good enough.

As a beginner myself I feel proud when I can see some stars on my photos, I'm throwing celebratory parties when I can tell what bit of the sky those stars are from, etc.

Us beginners tend to be improving the whole time.  Each attempt is better than the last.

Ian

[andrew s]

What do you mean by too strong? Is the field of view too small to find the object of interest, is the mount not up to tracking, can you not get it focused etc. If you are clear what your problem is others might be able to advise. Getting any new system up and running can be a challenge even for seasoned observers.

Regards Andrew

[cfpendock]

Not necessarily too powerful, but not particularly easy either.  2000 mm focal length requires very precise tracking, particularly for the longer imaging time needed at f10.

Chris

[Astrosurf]

I never quite understand the terms 'fast' or 'slow' when it comes to scopes, but it's to do with how much light the scope picks up. F5 is a fast focal ratio. You can work it out by dividing the focal length by the aperture. Mine is 1000mm/200mm = 5. Yours is 2000mm/200mm = 10. That's pretty slow. The best objects for slow scopes are planets which are bright and also very small so need the long focal length.

It's not impossible though, but try on bright DSOs like globular clusters.

Good luck!

Alexxx

[iwols]

thanks for the replys guys what i mean is is the fov too small and instead of the full object i just get a close up of individual stars if that makes sense ,what is the best thing to work with in the sky tonight here in the uk

[cloudsweeper]

2 hours ago, Astrosurf said:

I never quite understand the terms 'fast' or 'slow' when it comes to scopes, but it's to do with how much light the scope picks up. F5 is a fast focal ratio. You can work it out by dividing the focal length by the aperture. Mine is 1000mm/200mm = 5. Yours is 2000mm/200mm = 10. That's pretty slow. The best objects for slow scopes are planets which are bright and also very small so need the long focal length.

It's not impossible though, but try on bright DSOs like globular clusters.

Good luck!

Alexxx

I believe it's a reference to cameras, where "fast" allows more light, so shorter exposure is required.  Bigger aperture (light gathering) for a given focal length.

My SCT is "slow" - f/10 - but is fine for DSOs, giving a FOV of about one-and-a-half (correction: three) Moons, which is plenty for all but the biggest DSOs.  And they won't usually be visible in their entireties.

Plus, the exit pupil with a slow 'scope is smaller, which is good for faint objects in polluted skies.

Doug.

[cloudsweeper]

29 minutes ago, iwols said:

thanks for the replys guys what i mean is is the fov too small and instead of the full object i just get a close up of individual stars if that makes sense ,what is the best thing to work with in the sky tonight here in the uk

Other than planets, open clusters make easy and very rewarding targets. 

Galaxies are fun to track down, but with poor skies, I've only seen them as fuzzy blobs so far!

Doug.

[iwols]

any inperticular please

[cloudsweeper]

2 minutes ago, iwols said:

any inperticular please

M45, M36, M44, M67, M35, M38 - these are amongst  the nicest I've seen so far.

[LukeSkywatcher]

M44 (the Beehive) gets my vote every time. Its just lovely. It was also Patrick Moore's favourite object in the night sky (apart from the Moon,i'm guessing).

[Stu]

Have a look at the astronomy tools site, enter your scope and camera details and you can see how the targets are framed.

http://astronomy.tools/calculators/field_of_view/

I would think that Globular clusters would be a good place to start, such as M13, M92 and M3.

[Xplode]

A C8 isn't a good scope beginner, both the long focal length and slow optics makes it very hard for a beginner to get good results.

Can you tell us morea bout your setup? Mount? Do you guide? Exact which C8 do you have?

 

 

[iwols]

hi i have the c8 edge, the sw ed80,  heq5 mount, qhy5 ii l mono camera and a d750 ,to use, unguided at the minute but use stellarium and stellarium scope.

[LukeSkywatcher]

56 minutes ago, Stu said:

Have a look at the astronomy tools site, enter your scope and camera details and you can see how the targets are framed.

http://astronomy.tools/calculators/field_of_view/

I would think that Globular clusters would be a good place to start, such as M13, M92 and M3.

I like that app. Never used it before. Ive used similar but this one is better.I have an 8se (similar in many ways to a C8) and globular clusters do look stunning. It could be because of the narrow(er) FOV which an SCT offers. I just tried a rendition of the Crab using my 8SE and a 25mm NPL. Brilliant............oodles of space around it and a nice size. I could easily kick up the magnification 200%.

p.s.~i know the Crab is not a globular cluster. Ive never targeted it before though.

[Xplode]

You should use the ED80 instead as it's both faster and shorter focal length. Do you have flattener/focal reducer for it?

Since you have a guidecam getting started with guiding should be your first priority. With guiding polar alignment isn't so critial (when  i had a portable setup i just centered polaris in the HEQ5 polarscope, it was enough for 5min images)

[iwols]

3 minutes ago, Xplode said:

You should use the ED80 instead as it's both faster and shorter focal length. Do you have flattener/focal reducer for it?

Since you have a guidecam getting started with guiding should be your first priority. With guiding polar alignment isn't so critial (when  i had a portable setup i just centered polaris in the HEQ5 polarscope, it was enough for 5min images)

no field reducer at the minute one of the reasons i tried the c8 was when i imaged orion nebular with the ed80 with my d750 and just wanted to get closer so i didnt have as much work to do cropping,but must say the final image i was pleased with,might try my ed80 again tonight(weather permitting)will the reducer work with the c8 as well

[cloudsweeper]

.........only for focal lengths up to about 25mm.

[iwols]

10 minutes ago, cloudsweeper said:

.........only for focal lengths up to about 25mm.

not sure what you mean by this

[cloudsweeper]

If you use a reducer in conjunction with eyepieces of 25mm and more, you will possibly get vignetting/distortion in the field of view.  A better approach is to use a 2 inch diagonal and EPs.

(Bear in mind I'm talking solely from the perspective of a visual-only observer!)

Doug.

[cjdawson]

20 hours ago, iwols said:

thanks for the replys guys what i mean is is the fov too small and instead of the full object i just get a close up of individual stars if that makes sense ,what is the best thing to work with in the sky tonight here in the uk

I've got a Meade LX-90, it's also a 2000mm focal length F/10 scope.   To help with the FOV issue, a focual reducer will help out.  I've got one that will drop the F ratio to F6.3 which if setup correctly will help, both in terms of exposure time and size of object.    Just be careful to make sure it's set to the correct distance from the chip in your camera otherwise you'll get reflections.

 

19 hours ago, iwols said:

hi i have the c8 edge, the sw ed80,  heq5 mount, qhy5 ii l mono camera and a d750 ,to use, unguided at the minute but use stellarium and stellarium scope.

Guiding is pretty much a must have for a cope of this power.  Without it, you will end up with a blurry image due to even the smallest misalignment, or even wear and tear on the drive mechanism causing periodic error.  Without an optical feedback (guiding) it will always be there.