Somerled7

1 hour ago, Erling G-P said:

I image with a 200PDS on a HEQ5.  Wind has to be quiet, as it's quite a sail, but apart from that, I get some ok results.  Why not give it a shot, if you have the equipment already ?

I might give it a go.  I tried a couple of years ago, but found it difficult to get a good focus as I don't have a 10:1 focuser and star images bounce around on the screen at the slightest touch.  Then I lost interest a bit.

Looks better than mine (no surprise there!!).  I have a 200P that I use for visual observing so I could try that for imaging, but I am guessing that would be too much scope for my HEQ5 mount.  

Whilst waiting for delivery of a Skywatcher ED80 , I'm trying out some camera lenses, partly to start learning about guiding and  also to give me a few images to practice processing.  Here's my first attempt at a galaxy - M101.  1hr 40mins total exposure time, made up of 15x 400s exposures (plus darks, flats and bias).   Taken with a Sigma 150-600mm zoom lens and EOS80D mounted on an HEQ5.  I know it's not brilliant and it really requires more exposure time, but I'm just pleased  to be able to see some spiral structure. 

Well I've had a quick go and answered my own question - it doesn't work!!  It's surprising how quickly the camera warms up - 1st image at +5degC, 2nd at +9degC, so there is probably quite a temperature difference in each frame.  So, if the important thing is to get stable ambient conditions, I have a conservatory which gets quite cold at night.  I can safely leave the camera to run over-night without having to monitor it.  It won't quite match the outside temperature, but a cold night in the conservatory might match a warmer night outside.  Incidentally, I don't see a problem with putting the camera in a fridge - I've shot landscape photographs down to -17degC, which is well below my fridge temperature!    

I've only tried a couple of imaging sessions so far, but already I'm thinking that taking dark frames at the end of each imaging session is eating into useful imaging time (or sleeping time!!) especially in the summer when nights are short.  So, what if I put my camera in a fridge, then take a series of dark frames as the camera warms up?  I'm using a Canon EOS80D and Backyard EOS which records the sensor temperature, so I could build up a library of different exposure/ISO/temperature combinations.  I assume that as the frames are supposed to be dark, the camera does not have to be connected to any lens/telescope, so taking them with the body cap on is OK?  If this is a viable approach, two questions:-

1) Would there be an 'expiry date' on the Dark Frames - I can imagine that pixels may fail from time to time giving a different hot/dead pixel array.

2) What would be a sensible temperature range that could be used when processing an image? 

Any advice welcome. 

Thanks guys.  I should have looked more closely at the instructions.  I've had a quick look now and I see the blinking arrows but I missed them in the dark.   

I recently bought the Synscan WiFi for my Heq5 mount.  Managed to get everything connected OK and then tried a star alignment.  When I chose a 1-star alignment on Vega, it slewed to about the right place, I then manually centered the scope and tried to tap on the icon to accept the alignment, but this did nothing, as if the icon was inactive.  When I tried a 2-star alignment (Vega and Arcturus) it accepted my first alignment on Vega OK, but then wouldn't accept the second alignment on Arcturus.  It seems as if it will not accept  the final alignment command.  I've tried on a few different nights and given up and gone back to the handset, which works no problem.  Anyone else had this experience?  I'm using the Android version of the synscan app.  

Thanks Olly, I tried that adjustment and it enhances the reds a bit, so one to remember.

17 hours ago, rickwayne said:

NOICE. So nice I'll forgive you for not having gone uphill both ways in the snow for several years with nothing but poo images to show for it, like some of us 🙂

If you'd care for a somewhat less simple tweak...see if you can obtain a standalone version of starnet++ and get that running. It's a neural-net processor that yanks the stars from your image so that you can process that gorgeous nebulosity independently. Then, when that's looking quite spectacular, you can blend the stars back in.

The idea is that when you stretch an image to map the dim tones onto most of the available tonal range, you inevitably lose saturation in the higher end. So by taking the stars away from that stretching process, you preserve their color, and also avoid enlarging them unduly. No criticism implied of your fine image, but you'll note that there's very little color in the stars. I bet you have plenty in the original data.

Thanks Rick, I'll look into it.  In stretching out the image, I did try masking off the stars in Photoshop at various stages,  but maybe not enough to preserve the colour.  

Thanks Olly,

I used Deep Sky Stacker with everything on default settings, then processed in Photoshop.  I'm quite familiar with Photoshop as I do a fair bit of photography, but using it for astro images is something new for me.

Hi all,

First post on Stargazers Lounge, though I've been looking at this site for quite a while.

I made an aborted attempt at astro-photography a couple of years ago, got a certain distance with it, but then gave up.  Under lock-down, all the clear nights recently have tempted me to have another go.  A couple of attempts in, and here's the first decent picture I've managed - The North American Nebula which is just starting to rise in the West.

This is taken with a Sigma 150-600mm zoom lens at 190mm mounted on an HEQ5 mount, and using a Skywatcher finder scope with a QHY5LII colour camera mounted on a side-bar for guiding.  The standard Sigma lens foot is far too flexible for astro work, so I've clamped up the lens barrel with another lens collar to mount it to rigidly to the dovetail bar.  At just 190mm, this arrangement seems rigid enough for tracking., and I managed 20*300s exposures before giving up at 3am.

Any comments/feedback or suggestions for improvement welcome.