vineyard

1 hour ago, matt_baker said:

It isn't actually, just one whole frame!

Wow, that is a perfect FOV.  I tried earlier in thelast yr w a 102mm at f/6.8 and just couldn't get it all to fit in a single shot.  Great stuff 👍🏾

Very ghostly - would be a great Halloween image as is.  Is this a mosaic btw?

That's really lovely 👍🏾.  There must be something in the air b/c I'm enjoying playing with a Pentax nifty fifty on an iOptron Skywatcher Pro - sometimes its nice to just go light-weight & wide!

It was the same here about 3 nights ago (as you can see from the photo in the other thread)!  V atmospheric 👍🏾

Hello,

So while testing out an old prime lens at the weekend (see other threads) I also pointed it in the general direction of Auriga & went away for 2 hours.  Here's a JPEG of what emerged (120 lights of 60s, calibrated & then ABE+HT).

The moon was very bright, there were passing high clouds, it was a cold night and there was a strong halo visible (are they called moon dogs?).  I guess that's what that ring is in the photo.

The stars themselves look pretty decent for an old 50mm (stopped down to f4)?  It really shows how sensitive these CMOS cameras are that they can capture that through these conditions.  I also thought I would test out astrometry.net to see if it could annotate the photo in spite of all the halo noise.  JPEG attached - it doesn't do too badly does it - although it missed M36, M37 & M38 (understandably given how the halo crosses them), I'm still pretty impressed by the ability of the software to do that!

Cheers,

Vin

Hi Stu, for me the second image of the last two is better - it has a more textured, 3D feel.  Completely agree w you on the less is more - I'm finding that a good guiding principle (even though s/times I like to blow it out just to see how weird it looks!).  I've never used Registax so can't comment on that, but I really like ImPPG (originally tipped towards it by @Rustedfor solar and I use it for both solar & lunar now, religiously).

(PS - can't believe you got those from an iPhone camera btw - I only have an old iPhone so I guess those cameras are a lot better now!)

So what with all these clouds & tier 4 lockdowns, I tinkered a bit more.  Here are 3 images - cropped & downsampled, then star-reduced, and also an annotated one from Astrometry.net (lots of objects!).

2 hours ago, Gina said:

For the Milky Way mosaic I have Asahi SMC Takumar 28mm f3.5 lenses.  From Cygnus to Orion - The Milky Way as an Ultra Widefield Mosaic - WIP

I also have 55mm f1.8 Super Takumar and 105mm f2.8 Takumar and 200mm f4 SMC Takumar lenses.

If that's the K type 28mm f3.5 that's a lovely lens!

Hello,

I got an old cheap 50mm f1.7 prime lens just before Christmas (about 40 yrs old I suspect - an old Pentax SMC).  And I thought I would experiment with it for some wide-field shots.  I stopped it down to f4.  60 lights of 60s last night, just pointed it up to Cassiopeia on an iOptron Skyguider Pro.  ASI294MCPro w CLSCCD filter between the lens and the sensor.  Darks, flats & dark flats applied.  Stacked in DSS w some minimal tinkering in PI.  JPG for size.

I guess that's vignetting in the corners - there is curvature as well, but since that's in the corners that would have to be cropped out, it's not a loss.  Is that the Pacman nebula, w the Heart Nebula at right hand edge & the double cluster?

What do folks think - is it worth persevering w this lens?  Had I framed it better, I could have positioned the Heart & Soul in the middle, and gone for much more data to see what emerged?

With an APS-C sensor, the 50mm effectively becomes about 75-80mm, so an alternative would be to look for a wider lens (Pentax used to do a great 28mm f3.5 K lens but that's pricey)?

Anyway, just some fun & quick experimentation!

Cheers & stay safe,

Vin

(PS - the weird shapes on the middle of the left hand side are the stacked silhouetted branches of a tree that came into the FOV as the mount rotated!)

This is going to be a great thread to follow, thank you.  The Ha & Oiii monochrome versions at the top are really nice.  Is there vignetting in the corners?  (I ask b/c I was tinkering w an old manual focus prime lens 50mm f1.7 - am just about to post a quick & dirty image in another thread, and I think I was getting vignetting).  If so will the vignetting increase the number of panels needed?  I'm going to learn by watching this thread! 🙏🏾

Nice! Just enjoying sunshine between clouds here :)

4 hours ago, happy-kat said:

Had to read up on that device. It's clever and small is you already have a Pentax but that makes its very niche.

Those at 60s look very useable. Did you try any longer ones to see at what point your experience bottomed out?

Hi, yes I suspect only Pentax have the patent for it (b/c otherwise any DSLR w image-shake compensation should be able to offer this?).

Unfortunately I didn't have time to test it methodically.  At 120s there was some trailing (but I didn't do a "Precise Calibration" option that is also apparently available, so maybe that would have made it a bit better).  There was too much LP to allow 120s anyway (even w lowest ISO).  Upto 80s was fine.  The sharpness seemed sensitive to the f-stop being used. I was silly (not being used to AP w DSLR) and left the ISO at 200 - I should have increased the ISO at the smaller apertures to see how much more could be captured even w 60-80s.  Will try to be a bit more methodical next time.

Pentax also has a "Composite" function in camera, which I think basically does some form of stacking (but w/o calibration I guess) and generates a single image.  I'm quite curious to see what that produces!

Cheers,

Vin

Hello,

I'd got a little GPS dongle for an old Pentax earlier this year so that the Astrotracer functionality could be used.  I thought I would try it out with an old 50mm SMC M f1.7 lens.  Here are 3 sample shots (JPEGs for size) - the first is a single shot of Hyades (60s, ISO 200, I can't remember the f-stop but it was definitely not wide open b/c the lens is definitely soft at f1.7 but gets much sharper stopped down).  The second is a stack (!) of 2 images of the Hyades.  The third is a stack of 3 (!) images of the Pleiades.  I use the word "stack" as tongue in cheek but I was curious to see what might emerge (only ABE & HT done, no calibration w darks or flats etc).

These were from Christmas Eve so the moon was out & BRIGHT (I had put a Baader M&SG filter on but even then no real chance w huge gradients).

All told I think this is a handy little thing for v mobile wide-field astro (just a camera, the GPS dongle which goes on the flash hotshoe & a tripod needed).  Best for dark skies I guess.  I want to try the AP capabilities of Pentax's std software a bit more just for fun.

Cheers all,

Vin

That is gorgeous.

6 hours ago, Kitsunegari said:

I agree, the second one in the most recent post is the most uniform.   The issue is not with processing,  it could realistically just be your focuser.   

 

Try using extension tubes and not the actual focus wheel on the scope.    This will sort out any slack in the focuser if there is any, could be that simple.

Thanks.  It is an old scope so that's a possibility - could a tilter help (I keep it for occasional NR but could just set it as part of the standard train)?  Cheers & stay safe

Running around like a headless chicken for about 20 mins.  Noticed clear skies, went out and could just see J & S rapidly disappearing into the SW.

Helter skelter getting the old Vixen Porta & Telementor up, and bingo.  Got them in 10-O - lovely.  Some Galilean moons strung out (incl one quite far from Jove?) and Saturn in the background presenting its rings beautifully.  Out of curiosity popped in a Nag Zoom and could take it to 4mm and still get both in the same FOV - although v mushy of course.  At 10-O it was v clear & sharp (nice banding on Jupiter).

If you can get clear sight & have an EQ mount tracking, you are in for a treat.

Over all too soon w clouds.  But still wonderful seeing this celestial dance.

Hello,

So I tried a couple of different approaches v quickly today.  Attached as JPEGs for size.  Same settings in ImPPG on both, and same High Passes in GIMP.  Nothing else done.  The seeing was better for the 2nd so there are more images stacked.

What are your views on which image has better tuning/illumination?

Thank you & stay safe!

Vin

That is v tasty! 👍🏾

25 minutes ago, Nigella Bryant said:

Hi vineyard, solar observation/imaging is completely different than any other form of imaging. Getting the tuning right is paramount for both to get the best out of your set up. I did do a tutorial on how to tune your ha scope a while back here on SGL. It's a learning curve but once mastered it's easy every time. The only caveat is when you have cloud going across the disk which makes it a little more difficult, not impossible, but a little more difficult. Found the title below.

Imaging Technique to attain on band HA and full illumination

Thanks - read that w interest.  Those are good tips to over-expose and then centre the illumination 🙏🏾 I will try those next time (I've just been so happy to see the sun that I've not been patient ).

Thanks @Nigella Bryantwill try that next time there's some sunshine - tbh, I've just liked what I've been able to see with it so much w the naked eye that I haven't tried the different tuner settings that methodically - will try that next time & report back.

PS - that is an amazing image btw!

That FOV really works well (assuming you'll only crop the bare minimum?). Gives a v nice sense of perspective. 👍🏾 

7 hours ago, Kitsunegari said:

There is some extreme banding which should not be there.      This brand of etalons are supposed to be completely uniform across the entire field.    

 

 

Here's a different whole disk image from the same session (PNG instead of JPEG).  I had done some sharpening on it (ImPPG & then High Pass in GIMP) and played a bit with levels.  What I can see is that the SE quadrant is slightly brighter, so is that the sign that tuning could have been better (or that something else is happening - hopefully not - w the blocking filter etc)?

Thanks @Kitsunegari I will try & check.  The mounting ring threads in finger tight, and then I thread the etalon on finger tight.  Could it be just that I need to try different settings on the tuning dial?  This was a demonstrator model that Helmut was using (hence I got a discount) & he did clean and field-test it before shipping.  Usual Solarscope philosophy of returns, fixing etc still holds, so I will look into it (not sure when the Sun comes up now!).

Is there anything in particular I should look for (just an even intensity on a stacked image - is there a way of telling that in live view mode b/c I've noticed that seeing varies so trying to see whether its tuning or just seeing is a learning curve I am still on!).

Cheers.

Hello,

Hope all safe & well. Managed to get some images yesterday in the lovely morning sunshine, and have been tinkering a bit w various processing approaches.  JPGs below for size.  Kit was TV76 w a SF-50 etalon (a treat to myself ) with an ASI178MC.  I think I will start researching mono cameras now!

Stay safe all,

Vin

Had a quick chance before clouds came in.  18.2mm Delite w TV76 and both comfortably visible (in about the middle 60% of the FOV so I guess that means it could have handled a shorter f/l - will try a 12mm next time I get a chance). 🤞🏾for 21st!