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Astro_king

Imaging targets for tonight - HELP!

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Hi,

I finally managed to get guiding to work on my C8 mounted on heq5.

I have only ever processed a picture of the moon so I want to collect as much data as I can tonight and then process over the weekend. I took a 10 min sub of the pleides but that was quite washed out at ISO 800 as the only LP filter I have is broadband.

I plan to take 20-30 dark frames once guiding works and then take 1 hour snapshots of each target. Would 200s each sub be best? or should I bring it down to 100s subs at ISO1600?

I would like to know what are the best targets for this setup? I have a 0.63x focal reducer that has really helped in making the field of view wide and flat.

First target is Andromeda, although big, I have always wanted to image it. What should be my other targets? It's meant to be clear for three nights in a row here! A RARE THING - I KNOW!

 Thanks.

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M33 is close by, which is always nice to get and not quite as large as Andromeda. Also, you could go for the Double Cluster too, if you want a change from galaxies. I hope to take advantage of the clear nights too, and I'll probably be going for M33.

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i don't know much about imaging, although i do plan on doing it at some point. but as for ideas, i personally would go for clusters, nebulae, and galaxies. if you want specific targets, you could try the crab nebula if its visible where and when you will be tonight. 

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Keep as far away from the moon as possible.  Also, go for bright targets - M31 and M33 have already been mentioned.  M81 and M82 should also be possible later in the evening.  A maximum of 200 seconds per sub should be ok, but as a maximum with the moonlight.  Others will be more expert, but I understand that there is no point going above ISO800.

Chris

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The main problem tonight -and getting worse by the day- is the moon. Last month at this time, I turned my attention to open clusters which don't suffer so much from the reduced exposure the moonlight imposes upon you. I tried ngc457, m103, ngc7788 and 7790. The last 2 are on a par with the more famous double cluster when imaged with a decent focal length. Here they are with m 6" Netwonian at 1200mm; you should be able to get closer still:) HTH.

Edited by alacant

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I feel if I get out later I would be looking northwards, M81/2 sound a good one, may even try it myself if it is not too low from here.

 

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To give you ideas, have a look at DSO browser - https://dso-browser.com/dso/search - login with your location and change the search parameters to something that will accomodate the moon. For instance i had mine just set to bright nebulae and diffuse nebulae but i see you have to do broadband so you can reset this as you please. The little graph by the search results that plots altitude and time is particularly useful.

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I take it you can guide a c8 for 10 mins? 

Iso will be dictated on how bright the moon is to your target,and how long you expose for..

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18 hours ago, alacant said:

The main problem tonight -and getting worse by the day- is the moon. Last month at this time, I turned my attention to open clusters which don't suffer so much from the reduced exposure the moonlight imposes upon you. I tried ngc457, m103, ngc7788 and 7790. The last 2 are on a par with the more famous double cluster when imaged with a decent focal length. Here they are with m 6" Netwonian at 1200mm; you should be able to get closer still:) HTH.

Thanks mate,

Will try and put them on my list.

Your image looks stunning!

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12 hours ago, newbie alert said:

I take it you can guide a c8 for 10 mins? 

Iso will be dictated on how bright the moon is to your target,and how long you expose for..

I did but at F6.3. Not even dared to try at F10. F10 really is for later on when I want to image small targets like M92 etc and planets next year.

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Thanks for the advise everyone!

I had a rough rough night!

I had decided to image Andromeda for an hour and then move on to M33. Double cluster I was going to image the next say.

So I have an observatory i have just built and proper DSO imaging only kicked off last night with the setup working. Here's the summary:

 

Roll off roof and get the setup ready and perform star alignment. Old laptop dedicated at the observatory crashed, upon reboot had to wait for windows updates!!!

Anyway, upon reboot I got alignment going again and once star was centered, hovered on to andromeda and started imaging. Tried 60 seconds, 120 seconds etc and decided to settle for 90 seconds, don't know just instincts said 90 seconds at ISO800.

Decided to take darks in the end. PHD guiding didn't work for what felt like forever! In the end had to change calibration ms to 3000! and then it worked but it took about 3-4 minutes before guiding kicked in.

Decided to take 40 lights at 91s ISO800, went to hangout with my daughter came back in between and was shocked to see PHD had given up on me and had lost the star, which by now had moved up!

Andromeda wasn't centered anymore which let me to try to re-centre it. Since it was on dead zenith, as soon as I pressed CTRL+1, the scope did a full 360 degree on me to reach andromeda. It never found it, very weird. I went back to the observatory (I remotely control my obsy laptop using team viewer), and was trying to work things around when the laptop died on me again! Had to do ALL the setup work all over again including guiding! looked at the 0.63 focal reducer and it had gone misty, brought my wife's hair dryer and gave it a clean. Removed the dew shield and removed the dew on the corrector plate of the C8 as well.

Back to imaging and still can't find andromeda. Tried M33, can't find it either. So decided to look for double cluster. Found it upon first attempt so go to was working! Anyway, took 20 snaps of double cluster at ISO800. Then decided to call it a day and closed the roof of the obsy, turned everything off apart from the laptop and camera to take dark frames.

After 6 dark frames the camera disconnected only to intermittently connect back. Didn't have the courage to go out again and reset it. Will attempt things again tonight.

Imaging is soo much more tougher than visual observing!!!

Lessons learnt:

Need a new laptop!

C8 with focal reducer isn't good for imaging large DSOs at all. The stars vignette quite badly towards the edges. Also, you don't get a full image anyway, there is this circle in the image caused by the long T-ring+LP filter when using the 1.25 tube instead of 2".

As planned before, when I was building the observatory after discussions on this forum with other people, I might have to buy a refractor to mount on top of the C8 earlier than I thought. Possibly the new WO61.

Attached are raw image files of Double Cluster and Andromeda at 91sec ISO800.

Thanks for reading, any thing you could advise me on, please feel free to comment.

Clear skies.

L_0004_ISO800_91s__10C.JPG

L_0028_ISO800_91s__7C.JPG

Edited by Astro_king
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48 minutes ago, Astro_king said:

Imaging is soo much more tougher than visual observing!!!

 

Yes, 100x this!! Once I had come to the same realisation I started to break down each session into just achieving one goal before moving on (e.g. getting setup in a reasonable time, polar alignment, framing/focus, guiding etc.), and getting any images at all was just a bonus. It's taken nearly two years, but I'm at the point now where I'm confident I'll have a good set of images at the end of the night, which just leaves processing as the last goal to tick off!

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11 minutes ago, Mered said:

 

Yes, 100x this!! Once I had come to the same realisation I started to break down each session into just achieving one goal before moving on (e.g. getting setup in a reasonable time, polar alignment, framing/focus, guiding etc.), and getting any images at all was just a bonus. It's taken nearly two years, but I'm at the point now where I'm confident I'll have a good set of images at the end of the night, which just leaves processing as the last goal to tick off!

This is where I thought if I have an observatory, scope polar aligned and balanced at all times, all wires connected and a dedicated laptop at the obsy, it should be roll off roof and off you go into image land situation. Boy was I wrong!!!

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Progress is hard when learning, but my advice would be master the taking and use of flats, they will be infinitely more useful than darks.

Probably the most important calibration frame.

Also, (and I used to do this), don't ping between targets all night, pick one and gather as many lights as you can otherwise you'll have mediocre results on 2 or 3 targets, rather than a lot of data to play with on 1 target.

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1 hour ago, Astro_king said:

C8 with focal reducer isn't good for imaging large DSOs at all. The stars vignette quite badly towards the edges. Also, you don't get a full image anyway, there is this circle in the image caused by the long T-ring+LP filter when using the 1.25 tube instead of 2".

Hi Astro_king,

The graduated light circle (bright center, darkening towards the edge FOV) you are seeing there is the typical vignette that you will get with a focal reducer which will be corrected by applying flats shot through the focal reducer. There is something else going on though as the stars at the edge still show some coma and possibly lack of focus as they show a part circle with dark centre. What do you use to obtain focus? The stars at center of image look round with good star colour so applying flats then cropping out the extreme edge would leave you with a pretty good final image I think.

FWIW I have had similar experience with my now 1 year old ROR Obs introducing yet more hurdles into this hobby, comms being top of that list for me, but once you get those sorted you will definitely reap the benefits.

Good luck, Geof

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With a C8 I'd be having a look at M1, as your FL is long enough to do it justice.

M31 and M33 are *big*, also M33, although theoretically bright has a very low surface brightness, lower than a lot of smaller, nominally fainter galaxies. I tried M33 last year, and just gave up as I was banging my head against a brick wall trying to get anything even half way decent. This was with my 130 f/7 apo and cooled CCD camera. I wouldn't want to try it at f/8 with a DSLR.

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10 hours ago, Astro_king said:

I did but at F6.3. Not even dared to try at F10. F10 really is for later on when I want to image small targets like M92 etc and planets next year.

F ratio isn't really what you been to look at..its the focal length..as a example the c8 at f6.3 the focal length is at around 1260mm from 2003mm...a skywatcher 80ed  has a native focal length of 600mm,with a .85 reducer it's at f6.37..but it's focal length is now at 510mm ...so even thou the f ratio are similar..the c8 is more taxing on the mount than the 80ed..

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Hi again,

 

I had the most frustrating night of my life last night. Second clear night in a row and I wanted to make the most of it to correct things pointed out in this thread like bad focus etc etc and attempt the double cluster again.

 

however, I tried to connect the laptop to the mount and the laptop crashed. It crashed due to EQDIR cable I know this by now. I rebooted and it crashed again upon successfully connecting to the mount. Upon the next reboot, eqmod refused to work and threw a 55 file already in use error. I rebooted multiple times but the error never went. I had to remove EQMOD and ASCOM completely. Reinstalled and had the same problem. I looked online and found some files to delete namely EQMOD.ini and joystick.ini and other files in c:/users/<pc name>/AppData/Roaming/EQMOD. If you get the 66 error than that means you need to delete joystick.ini and other files too.

 

That said, now eqmod finally opened up but refused to connect to the mount. I removed eqmod and ascom again and it still didnt connect.

By this time, I had been trying to get the laptop to connect to the mount for hours and the observatory had turned into an igloo, I could see ice built everywhere! The wooden frame, the telescope's cap, it was freezing cold, chilling to the bone!

I got soo fed up, and determined to make something out of the night, I just connected the handset and pointed to the moon, took some pictures and called it a day.

Attached is the processed picture of the moon, 100 subs at 1/400sec aligned in PIPP stacked in Registax6.

DSO imaging is not for the faint hearted!

 

 

 

png moon 29:11:2017.png

Edited by Astro_king
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the moon looks good, nice detail. hopefully tonight will be better, if you decide to try again. something you can try is to make sure that the laptop will connect with the mount BEFORE its time to use it, like test it during the daytime rather than wait till night. good luck!!

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That is unlucky!

Next time try without guiding, you won't be able to get long exposure times, but it will probably help you to get an image.

One you feel comfortable getting a semi-decent image without guiding, then try and tackle the software portion.

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Hi guys,

Thanks for your advise. Yes so the laptop always crashed occasionally but the mount always worked when it would start again. This time, it crashed and now the mount doesn't connect at all. The mount is fine as it works with the hand controller.

 

Anyway, time for update of night number 3:

For starters I can't believe I am writing this! Three clear nights in a row. I know this will never happen again until maybe decades later.

But I finished work and went straight to the observatory, didn't even enter home (i know dedication :)). Anyway, I didn't want to image any DSOs without guiding/mount control as the object moves fast without guiding and with no telescope control this would have meant me manually bringing the object back in centre. I intend to buy a new laptop and fix this issue for good.

 

With that said, I homed in on some visual observing and this is where the setup comes to life, open roll of roof, turn heq5 on, quick 3 star align and I was looking at andromeda, no hassle! Looked at andromeda, then moved to double cluster which is always a treat to the eye. Then before I could slew into more targets, the imaging bug bit me again. I pointed the scope towards uranus and looked at it through 25mm and then 10mm eye piece. At 10mm eyepiece, it looked like a small tiny disk and was clear enough but no colour. This was at 2000m focal length, F10 on the C8. I tried using my 6mm eyepiece and it couldn't resolve it to a clear disk. This is where I decided to test my eyepiece projection kit I bought 4 years ago but never used.

Tried the 25mm eyepiece and uranus was visible on the DSLR. Tried the 10mm eyepiece and it was much bigger but didn't resolve to a clear disk. Took over 100 subs at ISO1600 0.5sec each on 25mm eyepiece. Then tried to take some zoomed in pictures of the moon using eyepiece projection but it wasn't very rewarding so decided to call it a night.

Later on when looking at images, I felt gutted when I did a quick process on the picture obtained using 10mm eyepiece projection. Uranus was quite big and a lot of detail could easily be taken out post processing. I couldn't carry on using 10mm eyepiece because it was too difficult to keep uranus in centre and eventually I lost it completely and couldn't centre it again. This is where guiding would have helped massively as it would have kept uranus in centre as the FOV becomes very tight at 10mm eyepiece projection.

I also wish I had not used ISO1600 as the noise was quite bad and also should have taken some dark frames. Attached is a picture of uranus with mild processing of 1x raw sub at ISO1600 and 10mm eyepiece projection. Uranus is definitely the target I will image next but will try ISO200 with longer exposure and 10mm projection along with dark frames to hopefully bring a better end result.

Any thing you feel needs pointing out please feel free to let me know.

Clear Skies.

uranus .png

uranus zoomed in edited.png

L_0107_ISO1600_0.5s__6C.JPG

L_0120_ISO200_0.3s__7C.JPG

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11 minutes ago, Some Dude With A Mak- Cass said:

nice views of uranus, they look really good! what kind of scope are you using again?

C8 with eyepiece projection on canon 450D. In the picture where Uranus is a dot, I have used 25mm eye piece and where is is slightly bigger, I have used a 10mm eye piece. The zoomed in picture is the one taken from the 10mm eye piece which made me realise what was possible had I taken 100 or so subs at 10mm eye piece projection and stacked them together along with some dark frames to remove noise. 

 

 

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6 hours ago, Some Dude With A Mak- Cass said:

nice views of uranus, they look really good! what kind of scope are you using again?

I just tried processing the single frame in adobe lightroom and very pleased with the result!

you can actually make out some ongoing storm movement. See below.

IMG_0855.jpg

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I'm in the same boat as you, all fall it has been one technical issue after another on the limited cleat nights I've had.

But the fact that it is hard is what makes it so satisfying when you finally get some good data.

The last few sessions I have focused on getting setup right and with good PA, getting data has been secondary. Last night I think it paid off, with some of the cleanest subs I've ever had.

Target was just a simple open cluster due to the moon.

Computer is processing data right now. ?

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