Laurin Dave

You'll need either the 1x flattener or the 0.77x reducer/flattener  with that, depends on what camera you have /fov / sample rate you want  ...  £196 or £299..  

I’d just do 1-4 if I were you..  😉 and as another thought what filters are you using (some are too tall and rub on the faceplate) and are they securely located 

If you’ve not done so perhaps  recalibrating the filter wheel will help..  

Dave

Very nice Goran, the Ha really lifts it..   Do you know what's causing the Bhatinov Mask like spikes on some of your brighter stars?  @tooth_dr had similar on one of his recent images taken with the same camera

Dave

Interesting comparison and quite a difference ..  I’d guess that the big halos in the Oiii are reflections off the filters with the smaller artefacts being caused by  microlens/sensor window reflections 

If new it comes with 11 mm and 21 mm T2 spacers and a 16.5mm T2 to m48 spacer which with the 6.5mm camera back focus gives 55 mm 

Do you not have the 8mm thick M66 to M48 DSLR adapter? This is usually screwed onto the flattener and takes it to 55mm required backfocus and ZWO cameras come with the necessary extension tubes to give 55m

For further comparison here is another Rosette shot last Saturday night from Bortle4/5 in the UK and with the Moons at 76% and near the Hyades..    20x 1200s , Astrodon 5nm, Esprit100, SX46 (Kaf16200 ccd) Mesu...    luckily the Rosette is bright.

Somewhat lower SNR than Olly's but still pretty good..  If the Baader really is 4.5nm then it ought to be pretty close to the Astrodons..  With your Oiii and Sii filters if you do get halos there are processing methods to mitigate them including of course StarNet., there are plenty of excellent SHO images around that weren't taken with Astrodons or Chromas.   Also you might find, like I have that you much prefer imaging in "natural colour" ..  

Dave

Despite having numerous Astrodons in both 1.25" and 2" I'd agree with Steve.. save your money and put it towards that new ASI2600/QHY268 mono camera...  I would expect that the absence of any microlensing artefacts around bright stars will be far more noticeable than any improvement you might see from using Astrodon NB filters. 

Dave 

1 minute ago, Tommohawk said:

Shapstar 61 and ASI1600 cool.  Re M45 I got a good result in RGB, and was trying to see if I could improve it with L - but it wasnt a fair test due to moon and slight high cloud so will have to wait for another chance.

That might be a side effect of microlensing with the camera o..  in my experience its worse with Lum, but is dependant on exact scope/reducer/filter configuration, 

HI Tom

I've just checked my M45 and the Blue nebula is RGB 20:30:40 or thereabouts...  What scope and camera are you using? 

Dave

6 minutes ago, Xsubmariner said:

Hi Neil,

I don’t believe you can go wrong with the Mesu MK2, it is definitely a mount that does what it says, unlike some other mounts I have tried.  Your camera choice is interesting, while I have a mix of Cmos and CCD camera’s (QHY, ZWO & SX) my last three additions are all IMX455/571 sensor based units. These sensors offer considerable improvement over the older Cmos sensors and are worthy of some investigation.

I'd agree ... look at the newer CMOS cameras which do not suffer from the microlensing (which I believe the Horizon does) and which also have higher QE..  alternatively you might pick up a bargain CCD as folk switch over to the 455/571 chips, there was an Atik KAF8300 on here last week at a very good price and there have been KAF16200 cameras about too .. the 10 or 20 or 30 minute subs required with these are not an issue with the Mesu  ... although cloud always can be...  Also the Esprit120 can do full frame ... 

Dave

If the filters aren't parfocal then I'd expect that the FWHM you get with the luminance filter will be worse than the individual RGB filters, how much worse will depend on how well or poorly colour corrected the scope is..  It will be in focus though, or as in focus as it can be.  Also if you are shooting LRGB then generally it is best to shoot L when the target is highest/the seeing is best and the effects of the atmosphere are at their least.   Also I'd have thought that the photons that come through to constitute your luminance will depend on the colour of the target..  you can see this by looking at an unstretched RGB image  eg in a random sample within the core of M42  the RGB ratio of a Red bit is 80:25:35 and a Blue bit  30:32:38...

HTH

Dave

I've wondered about this too... just Googled it and Don W says both @PhotoGav and @tooth_dr suggestions work but that the 'track object' in Skyview only works for Moon Sun and a couple of planets (doesn't say which ones)

Dave

Hi Adam

I'm using Darks and 100 Gain and it seems to work fine..  I suspect that for bright stuff that Darks are somewhat optional although you'll  need to use them or bias to calibrate flats.   SGPro shows as B&W .. its a bit alarming at first

Dave

On 12/01/2021 at 20:03, ollypenrice said:

I'm a great fan of the mosaic and have just done an Astronomy Now article, I think for the next edition, on one approach to constructing them from individual panels.  The project in question began with APP but wandered off into Registar and Photoshop as well. (My fault!) So, having done a few big ones of my own, and having participated in two absolute giants, I thought I knew how to do it. Then, last week, I was given a 12 panel M31 dataset to try and construct. Hmmm... So far I am not succeeding. What's difficult is that only a small number of panels have any background sky to use as a calibration reference. I suspect that software aiming to do it all in one click has exactly the same problem, which is why it fails. So, I'm sorry to say that I don't have the answer on how to build a seamless and even M31 galaxy mosaic. I think I would be able to do it if I had a smaller number of panels, most of them containing at least a bit of background sky.

Difficult! But that's why we like it.

Olly

Hi Olly 

Based on what it managed to do on Steve's data the Pixinsight Photometric Mosaic script might be worth a try on this,   the script could use your wide field M31 RGB and Lum data to remove complex gradients from the high res panels..  

HTH

Dave

Steve kindly sent me his data so that I could try out the new Pixinsight Photometric Mosaic Script that I mentioned in an earlier post.  I already had an M31 taken with my Esprit100/SX46 which captures nearly all of Steve's fov in one frame.  After registering everything together using Pixinsight's Platesolving and Mosaic by Co-ordinates scripts  I firstly used the script and my M31 data to remove the gradients from Steve's higher res data, I then used the script again to combine the High res data as a mosaic and finally again to pad out the high res data with a wider star field.  The resulting L and RGB images were then processed in Pixinsight and Photoshop....

Here's the result....   not perfect with a number of joins and other artefacts visible if you pixel peep but otherwise speaks for itself and the power of the the new script..  Great detail from the Esprit150 too..  

Dave

Edited 19Jan21....  reprocess to remove the magenta halo which in my rush to post last night  failed to notice...   also added a version with Ha data 

With added Ha jewels..

I’d suggest you email Starlight Instruments with the dimensions of your focuser and seek their help ..   you’ll get the right answer that way ..   they’re usually pretty quick to respond 

15 minutes ago, Jt_3232 said:

Hi guys, this is my first post ever on this website. I got an Esprit 120 used with a Feather Touch focuser. Its drawtube is not long enough at all, so it came with a spacer. However, the spacer's threads aren't great and are the cause of some slight tilt. Do you think adding a 0.75x reducer/flattener will fix the issues with our focusing distance? I figured this thought might be useful for you guys as well as me.

Jaxon

Does your scope have a Riser between the Adapter and the Focuser? Have a look on the Starlight Instruments website to see what these are ..  the Riser is basically a tube that puts the focuser at the correct distance ..  if you have the flattener this should screw onto the focuser draw tube direct (via what’s known as an End Cap)..  so the configuration would be scope..  adapter..  riser..  focuser..  end cap..  flattener..  spacers.. camera 

HTH

ps I don’t think the Skywatcher reducer will screw into the Starlight draw tube ..  

That's very good, excellent considering how new you are to all this.

Well done

Dave

I’d just give it a go Andy and see what you get..  btw a larger fov will make gradient removal easier 

And its free!   I cant see why you 'd lose any detail on your target Andy   ..  your image scale will be 0.8arcsecpp but you'll be seeing/mount limited any way

Dave

I'd just use your 268 and crop your images if needed, however you'll often find (as I do with my Esprit150 and APSH chip ) that there are numerous smaller and not so small galaxies in the fov which give interest and context, also there are various galaxy groupings where the native 268's fov of view would work very well... eg Markarians Chain and neighbours .. Leo Triplet ..  M81 M82 and neighbours 

I bought some Televues to go with my Meade 10" LX200...  I was chasing fov .   They're very nice but gave no meaningful increase in fov above the 1.25" 62deg 24mm Meade eyepieces/0.63 reducer combo I already had. 

Dave

I believe that your fov will be limited by the telescope field stop to 46/2350 x57.3deg ie to 1.12deg and that no eyepiece/reducer combo will exceed this ..   It can be quite an expensive lesson to learn as I found out !

Dave