A small part of the Sadr Region

[Menno555]

I've never made a deep sky mosaic, so decided for a simple 2-part mosaic of a busy part of the sky at 2032mm focal length: the Sadr Region.
Became a bit of a frustration object cause of the weather: in 2 months I gathered just 2 x 2.5 hours of data
But here the result. Could be way batter but I really want to focus on small(er) object, so I call this a day.

For reference, here what part I did capture. Star in the left upper corner is Sadr.

ref.jpg (485.12 KiB) Viewed 5419 times

Filters used are the Optolong L-eNhance and L-eXtreme
The grey scale version is Ha only. Made it gray scale because it's way easier to look at and it gives a nice result.
The colour version is RGB Ha/OIII. Not really satisfied with it cause of the only 2.5 hours data for each panel, but it is what it is.
For the original size (3600 x 4000px), right click the image and choose to open in a new tab in your browser.
For reference: in this FOV you could just fit 2 full moons.







Bortle 6/7
Meade LX200 8" f/10 ACF OTA
Ioptron CEM25EC mount (no guiding)
Optolong L-eNhance filter
Optolong L-eXtreme filter
Zwo ASI071MC Pro camera

Captured with SharpCap Pro @ -10 Celsius / White balance R50 B50
L-eNhance: 2 x (18 x 300sec / Gain 90 / Offset 4)
L-eXtreme: 2 x (6 x 600sec / Gain 90 / Offset 4)
Darks + (dark)flats

Stacked with SiriL (m.b.v. SiriLic)

Mosaic made with Microsoft ICE

Processed in SiriL and Photoshop

[admin]

Hi Menno,

very nice - I think you are right that the mono version has a bit more to it than the colour one, but the colour one is still nicely smooth without colour noise or anything like that.

I can't see any sign of the stitching point between the two panels, so that must have aligned really nicely.

cheers,

Robin

[turfpit]

Menno

Turned out well - no seams visible. Mosaics are hard work, don't underestimate the time taken to accumulate the panels. Leandro and I found that out with viewtopic.php?t=7696. It took 16 nights with 2 months of elapsed time to acquire 4 panels of data.

Dave

[Menno555]

Thanks Robin and Dave
I made an overlap of around 25% and I used Microsoft ICE to stitch the two panels. I know it does a great job with moon mosaics but was not sure about deepsky like this. So in Photoshop I used it as layer on an existing pro capture of that area and all stars, clouds and regions did correspond with it.

Menno

[timh]

Hello Menno,

That came out pretty well. I have wondered about trying mosaics for deepsky because it seems attractive to get the best of both worlds - the detail of long focus plus a wider field although as Dave (turfpit) mentioned it must be a lot of work when you also need to accumulate images over hours rather than minutes as for the moon. On the few clear nights we have had here I have been using the refractor down at at 620 mm (very fortunate to have that as an alternative set up) to capture a couple of the big autumn nebulae.

There is so much detail in the HA images - the greyscale does somehow lseem to bring it out better

Tim

[Menno555]

Thanks Tim!
It's indeed more work with capturing but indeed the best of both worlds. Now that Andromeda is getting higher, I maybe going to try a mosaic of it.
But this means with my 2000mm FL a mosaic of 10 or 12 parts. And with the amount of clear skies here (less then minimal ), it's doubtful if I can get all of that. We'll see

Menno

[turfpit]

Menno

12 panels is ambitious - given the weather and the moon, how many years have you got?

I am trying some mosaics this winter and have put some time into planning based on the experience with the Carina Nebula viewtopic.php?t=7696. The star Eta Carina was used as the 'anchor' for the 4 panels. Not all objects will have a convenient anchor for ensuring the panel overlaps.

First step was to use the Telescopius Mosaic Planner at https://telescopius.com/telescope-simulator. Fill in camera, scope and object, then work out how many panels are needed. This will produce a list of the co-ordinates of the centre of each panel.

My first objects are planned to be M31 (2 panel) and Heart and Soul Nebula (6 panel) using an Altair 183M with an F5 420mm focal length scope. The plan is to capture HaLRGB for M31 and HaOIII+RGB for the Heart & Soul.

The problem I am considering is capture a panel completely with all filters then move on to the next panel or capture all panels in one night with a filter then move on to the next filter the next clear night. For example if I have 2 hours visibility for an object and 6 panels then a night's capture will be 20 minutes on each panel using a single filter. That gives me enough data to enable stitching the panels and leaves me with something complete. The other option might never have anything completed. Plus if I have an overlap problem I find out sooner rather than later. I do not intend to do battle with the meridian. Capturing all panels with one filter per night will cut down on time required for focusing and flats.

Just some thoughts - I will find out as November progresses.

Dave

[Menno555]

True, it's very ambitious. Especially now that I did see on the site you mentioned, I would need around 18 parts
So yeah, I might not do that

Menno

[turfpit]

Menno

I have found the Telescopius site very useful.

Dave

[timh]

Getting a good mosaic of something big like the North America nebula does seem pretty daunting. With many of these NB targets I always rather resent the amount of time spent accumulating OIII information when - in the end- it only really contributes colour information in regions coinciding with a stronger and more structurally detailed HA signal. It means having access to a second shorter focus optic and ideally another camera but a more efficient strategy might be to to take wider angle less detailed RGB and OIII images up at > 1.5 arcsec/ pixel for colour and reserve the detail and luminance for mosaicing just the HA as a patchwork to build onto wider angle background? For many objects I don't think that much would be lost?