Is this as good as I can expect with my current setup?

[Steve143]

Hi,

As an absolute beginner to astrophotography I have been capturing images to practice my image processing. I recently bought Affinity Photo and produced the image of the Pleiades below. 

I took 100 light frames at 2 second exposures, 30 dark frames and 30 bias frames. The frames were taken with a Canon EOS 70D fitted with a Samyang 135mm f2.0, on a static tripod (no tracking or guiding). I used ISO 1600 from a Bortle 7 location.

The frames were stacked and processed in Affinity Photo (curves and levels adjustments only).

Given the small amount of integration time do you think this is as good an image as I can get? I was surprised that I managed to pick up the hint of some nebulosity around the main stars. 

I've just acquired a SW EQM35 GOTO mount which will help with longer exposures, but still waiting for some clear nights so I can get out and practice setting it up. 

I've got so much to learn with capturing and processing images! 

Thanks for reading.

Steve 

[Budgie1]

For a total of 3 minutes and 20 seconds, I think you've done alright. You're starting to see the nebulosity around the main stars and this will only increase with more integration time. 

It looks like the focus maybe slightly out, I got a Bahtinov Mask for my Samyang 135mm F2 and it makes life so much easier.  

When you get your new mount you should be able to get exposures of up to 2 minutes, but start off with something like 30 seconds and slowly increase until you start to see elongated stars and then back off the exposure until they are round stars again. Polar Alignment is important to good tracking, so check out some YouTube videos on how to do this if you're not familiar with it.

[ONIKKINEN]

You may find that the EQM-35 does not perform all that well, at least probably not completely trouble free. If you plan on shooting unguided with it you should definitely "train" the periodic error correction in the mount. My mount came with a not very helpful PE curve out of the factory that didn't seem to do anything to the periodic error. Training it can improve things quite a lot, and for your 6 arcsec/pixel resolution should work well.

Read through the manual, there is a section on the periodic error in there. Basically you should point the mount somewhere south to as close to DEC 0 as possible, but still high in the sky, so depending on your latitude and location might not be all that close to DEC 0. Center on a star bright enough to be visible in live view, zoom in on the star as far as you can and then manually guide the star for about 8 minutes if i remember correctly? The better you do this the better your results will be in the end. If you dont do this, you shouldn't expect exposures longer than a minute to always have round stars as the periodic error can be quite aggressive on the mount.

Picture looks pretty good for what it is, an untracked short exposuretime from light pollution 👍. Although your list does not mention flat frames, which would be the most important of the calibration frames so definitely look into that.

[PeterCPC]

8 hours ago, Budgie1 said:

For a total of 3 minutes and 20 seconds, I think you've done alright. You're starting to see the nebulosity around the main stars and this will only increase with more integration time. 

It looks like the focus maybe slightly out, I got a Bahtinov Mask for my Samyang 135mm F2 and it makes life so much easier.  

When you get your new mount you should be able to get exposures of up to 2 minutes, but start off with something like 30 seconds and slowly increase until you start to see elongated stars and then back off the exposure until they are round stars again. Polar Alignment is important to good tracking, so check out some YouTube videos on how to do this if you're not familiar with it.

@Budgie11 Isaw these but wondered how easy they were to remove without disturbing the focus.

[Steve143]

7 hours ago, ONIKKINEN said:

Although your list does not mention flat frames, which would be the most important of the calibration frames so definitely look into that.

I didn't take any flats but will try that next time. Thanks! 

[carastro]

2secs is very short for deep sky objects even bright ones.  a tracking mount will help you get longer exposures and guiding even longer.   

Your new mount will help with this, I have a feeling I know someone with the same mount and his imaging has really stepped up a notch since he bought it and the guiding equipment.

 

Carole

[Budgie1]

2 hours ago, PeterCPC said:

@Budgie11 Isaw these but wondered how easy they were to remove without disturbing the focus.

The focus on the Samyang is quite tight, so pulling the Bahtinov Mask off the shield isn't an issue. I don't push the mask all the way on either, it sort of just sits on the end of the lens as I point at the star I using for focus before I put the mask on the lens. Using the 10x zoom function on the camera screen also makes life easier.