Last night's good Melbourne weather gave me 3h36 of integration on the Rosette nebula. Sadly, I had to throw out two and half hours from after the meridian flip because stars went badly out of focus after the flip for some reason (?). Would have got over 6h, but still, I am really happy with this result. I am in two minds as to whether I should add a few hours of data or just have fun and move on!
Strange star shapes in top left corner. Any advice?
Please feel free to comment and offer helpful tips from future improvements.
Many thanks,
Stéphane
Integration: 72 x 3' = 3h36
Callibration: 30D, 40B, 20F
Camera: Nikon D7000 (ISO: 800)
Guiding: ASI120 MC (PHD2 error < 0.7)
OTA: Bintel BT200 f/5
Mount: EQ6-R pro
Filter: Optolong L-Extreme
Coma corrector: MPCC MkIII
Process: PixInsight, Adobe Lightroom
Looks pretty neat with good details. Can't see the stars shapes at that res so not a real bother in the overall picture. Likely the camera shifted in the focuser when doing the flip. It happens to a variety of scope designs when you do a meridian flip and the weight distribution changes. Best to refocus after a flip.
Thanks for the feedback Marc. Come to think of it, I did forget to lock the focuser, so perhaps something happened there. I didn't expect the camera's weight to budge it. Now I know!
Thanks for the feedback Marc. Come to think of it, I did forget to lock the focuser, so perhaps something happened there. I didn't expect the camera's weight to budge it. Now I know!
Once I had a whole refractor slide down the tube rings. It stopped at the dewshield. Tubes shrink with the cold.
Once I had a whole refractor slide down the tube rings. It stopped at the dewshield. Tubes shrink with the cold.
My worst nightmare. Thankfully yours didn’t slide onto the floor and smash. I overtighten counterweights, tube rings, etc, so much out of fear. The only thing I tighten with restraint are collimating screws as I heard that the Newtonian miror can crack.
This hobby has enormous potential for both satisfaction and disaster. I haven’t broken anything yet, but I have a feeling that that day is approaching…
Really nice image of the Rosette
Well done !!
Nothing stopping you now , full steam ahead !!!
The odd shaped stars in the areas towards the corners of the image look very much like coma to me as they are flared to the corners. Had the same issue with my 8” f5 newt with a Baader MCCP Mk3. After 2 weeks of experimenting, a 1mm spacer fixed my issue with the sensor now 56mm from the coma corrector instead of 55mm ( all scopes are different) If it was tilt or reverse flop in the camera you would most probably see the stars odd shaped in the same direction across the field.
Anyway, great work
Clear Skies
Martin
Very nice indeed. I only got an hour on my first attempt, not enough really. Waiting on my 0.8 flattener /reducer before trying again. It will probably be here before I get another good clear night...
Really nice image of the Rosette
Well done !!
Nothing stopping you now , full steam ahead !!!
The odd shaped stars in the areas towards the corners of the image look very much like coma to me as they are flared to the corners. Had the same issue with my 8” f5 newt with a Baader MCCP Mk3. After 2 weeks of experimenting, a 1mm spacer fixed my issue with the sensor now 56mm from the coma corrector instead of 55mm ( all scopes are different) If it was tilt or reverse flop in the camera you would most probably see the stars odd shaped in the same direction across the field.
Anyway, great work
Clear Skies
Martin
Thanks Martin! Yes I will need to buy a couple of 1mm spacers and experiment a little. Do you know where I can order some? Can’t seem to find anything under 3mm. Really not an issue at this stage, but would be nice to fix some day. I also need to get a Bahtinov mask rather than “guess” perfect focus.
Clear skies,
Stéphane
Quote:
Originally Posted by Mick
Nice
Thanks Mick
Quote:
Originally Posted by Drac0
Very nice indeed. I only got an hour on my first attempt, not enough really. Waiting on my 0.8 flattener /reducer before trying again. It will probably be here before I get another good clear night...
Funny you say that Mark about the .8 reducer. With artifact ms from stacking cropped out, I just can’t squeeze the whole thing in. One day, I might do a mosaic of 2 frames. That will be in the distant future though as I have a whole bunch of other DSOs to capture first
Quote:
Originally Posted by Anth10
Stephane,
Really like this - especially the central area very nice indeed.
Well done
A
Thanks Anthony. The darker center with those “swirls” make the Rosette such an interesting target. I’m glad this one turned out better than I hoped.
Thanks Martin! Yes I will need to buy a couple of 1mm spacers and experiment a little. Do you know where I can order some? Can’t seem to find anything under 3mm. Really not an issue at this stage, but would be nice to fix some day. I also need to get a Bahtinov mask rather than “guess” perfect focus.
Clear skies,
Stéphane
Stephane
You already have a Bahtinov mask , the spider vanes on your newt !!
Just find a single bright star somewhere near ( as long as it’s above 30 deg Alt ) your intended object around magnitude 1.50 to 2.50 and take a series of 10 sec subs ( does the Nikon have a zoom function, that allows you to really get tight focus or use your capture software with a zoom box or zoom in feature ) each time adjusting your focus so that the diffraction spikes on the Star are like sharp swords
That’s how I’ve been focusing for years , never lets me down, I now use APT and the thumbnails are a 5 x zoom so I get a great close in view. Works just as well with my L Extreme filter
I do check my focus again sometimes during the session if I see the stars are bloating a tad
I’ve never used an auto focuser and probably never will
As I said it’s never let me down
When I used my Canon 600D , I used the same method and BYEOS had a nifty zoom box so it worked really well
My focusing time would be 5 to 6 mins , the more times you do it the easier it becomes
Leave it to you if you want to use a mask
Cheers
Martin
PS I bought my spacers from Bintel but I’m sure there’s other suppliers around
Stephane
You already have a Bahtinov mask , the spider vanes on your newt !!
Just find a single bright star somewhere near ( as long as it’s above 30 deg Alt ) your intended object around magnitude 1.50 to 2.50 and take a series of 10 sec subs ( does the Nikon have a zoom function, that allows you to really get tight focus or use your capture software with a zoom box or zoom in feature ) each time adjusting your focus so that the diffraction spikes on the Star are like sharp swords
That’s how I’ve been focusing for years , never lets me down, I now use APT and the thumbnails are a 5 x zoom so I get a great close in view. Works just as well with my L Extreme filter
Martin, wow I did not know that the diffraction spikes could be used for focusing I can’t wait to try. Nina records the HFR of snapshots, but I find the recordings quite volatile & inconsistent. Sometimes a good old Bahtinov mask does the trick better! Or perhaps (more likely) I haven’t quite understood the measurements yet.
Can't see the stars shapes at that res so not a real bother in the overall picture. Likely the camera shifted in the focuser when doing the flip. It happens to a variety of scope designs when you do a meridian flip and the weight distribution changes. Best to refocus after a flip.
I can’t wait to try. Nina records the HFR of snapshots, but I find the recordings quite volatile & inconsistent. Sometimes a good old Bahtinov mask does the trick better! Or perhaps (more likely) I haven’t quite understood the measurements yet. 
Nice work!
