The Lazy Astronomer

Well this is quite the opposite to normal - easy to find DSOs but difficult to find the moon! 😁 Surely if the coordinates of the mount matched Stellarium, then it must be Stellarium that's wrong about the moon's position. Were there any stars near the moon that you could use to verify if Stellarium had the moon in the right place?

To save anyone else going through the CN topic, the files can now be downloaded from http://starnetastro.com/

That is likey to be blue bloat - the 72ed is a doublet, so not perfectly corrected for all wavelengths. I would think a UV/IR cut filter would help greatly with that, but like I said, you'd probably want one that also cuts the extreme ends of the blue and red wavelengths as well (I use the Astronomik L3 on my triplet). The L-extreme should also cure that problem as it's a narrowband filter and will cut pretty much all of the other wavelengths except those around ha and oiii, but bear in mind it is only suitable for emission nebulae, and yes, you will need longer exposures if you go down that route. This is a common misconception, and intuitively, it seems to make sense ("to capture fainter detail, I must expose longer"), but once you've reached your ideal minimum exposure time, the improvements are very marginal. There are a few ways around this: 1) stretch using curves and focus on stretching the lower end of the curve more than the higher end 2) create 2 copies of the image, stretch the first one for the best core and bright detail, stretch the second one for best faint detail and then blend the 2 together 3) use some kind of hdr processing algorithm to recover highlights, such as those offered in Startools, PI or other astro processing software (not sure if there's any equivalent in PS or the like) Bahtinovs are ok, but it can be very difficult to get precise focus with them. I'm not sure what software you're using for capture, but consider looking at hfr measurements when focusing, and trying to get the smallest number (if your capture software provides that information, which it should).

Woah, let's not jump straight into that! Unless it's damage to the coating or fungus growth, it's probably not serious. Fungus growth is very distinctive (spider web like patterns), so it should be possible to rule that out immediately. I reckon your options are: 1. Attempt to clean it to see if the marks are removed 2. Contact FLO (or wherever you brought it from) for their assessment 3. Do nothing, provided you can determine it's not fungus growth or damage to the coating (this is likey the best option)

That's very nice for a first attempt! For a critique, I would say the stars appear to have an elongated shape and are possibly a bit bloated - former may just be tracking errors and for the latter; do you use a UV/IR cut filter? If not, I'd recommend you look for one which cuts the lower end of the blues and upper end of the reds, such as the Astronomik L3. Looking at this image, l don't think you need shorter exposures. The core is not blown out, and I think the trapezium would be resolved if you could get tighter stars (improve tracking, focus, and reduce star bloat). It may also surprise you to learn you don't need longer exposures either. I've taken the equipment in your signature and made some assumptions for the calculation (72ed at native f ratio, unity gain and bortle 5 skies), and 20s is probably the ideal minimum exposure time for you (well, 19s actually). What this means is, you are already exposing properly - going longer will not net you any significant gains. When adding new data, yes, restack all frames from scratch. Take care to ensure the framing between nights is exactly the same (or as close as you can get it) to avoid having to do some heavy cropping of stacking artifacts.

Ha is not a suitable substitute for luminance on broadband targets such as m31. It can be blended into the red and/or luminance channels to add specific details but not replace them entirely.

Definitely interested too. With all the cloud of late, about the only thing to do is daydream about how much time to spend on the next project!

As above, share the linear stacked image, as well as acquisition info (for general advice) - I (or someone far more skilled/experienced) can run it through PI and/or Startools if you like (or any other processing software - those are just the ones I'm familiar with).

Another vote for NINA (it's fantastic). In terms of frames, then lights (obviously), darks, flats, and flat darks. Filter choice depends very much on the target. Galaxies and reflection nebulae generally lrgb only, although some galaxies can benefit from some ha blended in also. Emission nebulae can look nice in lrgb as well, even better in hargb or halrgb if you're looking to retain natural colouring. The hubble palette (or other narrowband palettes, such as hoo) work very nicely on emission nebulae too, but at that point you're in the realm of false colour imaging. Generally speaking, you wouldn't mix hso and lrgb, but if the target has a particularly strong source of oiii and/or sii then blending those into lrgb can look nice (but tricky to get right). Play around, find out what you like and what works on the sorts of targets you like to shoot.

Can't help, but following as I've got similar skies and would also like to know if this target would be done any sort of justice within a reasonable (12 - 24hrs) amount of integration time.

I keep thinking I need an observatory, the only issue is where I set up in my garden for the best views to the south (sort of in the middle, and near the house) would be a very odd place for a structure. Probably need to open up the view near the edge of the garden by cutting down a tree or two (but I hate the thought of that)...

To add a note to this: I've been playing around with using it on linear data, and it seems to only work properly if you run it with stf active. I'm not really sure why...? Also, the check box to create a star mask does not seem to generate satisfactory results when using linear data, so you have to do it manually by subtracting in pixelmath. Those little niggles aside, it seems to work very well at removing the stars. For background: I was trying to see if I could find an even easier (than EZ Decon) way to do deconvolution by removing stars while linear, doing deconvolution without the need for star masks or deringing, then adding stars back. The issues with SNv2 mentioned above took me an embarrassingly long time to figure out and I didn't quite get far enough along in the process to see if the process worked well or not - please someone tell me if you think what I'm trying to do is a stupid idea and won't work well because of some reason I've overlooked or haven't thought of!

You may or may not have seen already, but this might be of interest, certainly a speed improvement on my machine, and I've seen reports from CN along the same lines too:

What do your lights look like? If all good, then no. Bear in mind when you auto stretch a flat frame, it greatly exaggerates the appearance of the vignetting. On the linear image, there likely won't be that much difference in brightness between the centre and the edges.

Never has a vote been so universal. I think you have your answer ☺

55mm is correct for the Esprit. Just because it caused me a brief moment of confusion, make sure you measure your backfocus from the adaptor on the back of the flattener, not the flattener itself:

Hmm. Does anyone know how it works within PI? I used it on an image that was working on in 64-bit (I know, I know, overkill) - does it change the bit depth of the image down to 16? I think PI still thought it was working in 64-bit, because I got a warning about how it couldn't save a 64-bit jpeg when I saved finished image out.

Just curious: what made you settle on gain 0 vs unity (or higher) for rgb only?

V2 does have an option to remove stars on "linear' data (inverted commas because it does it by doing similar to as you described above - stretching>removing stars>restoring to linear)

And another late entry! I thought to myself "what does this thread need?" That's right, more Horsehead nebula. Haven't seen a starless* version, so here's my attempt, made up of 7 hours of Ha captured over a couple nights in early-mid Jan *well, almost starless - the GHS script in PI did such a good job of controlling Alnitak, it seemed wrong to leave it out!

Just a heads up to anyone interested and who doesn't already know, I've just discovered Starnet++ v2 was just released last week. There is a thread over on CN started by the developer with a link to download the files (not entirely sure if linking to a 'rival' forum is allowed, but if you Google "starnet v2" it'll be one of the top results). Initial images coming through on that thread seem to show good results vs starnet v1 - I'm currently downloading 👍 Edit: files removed from SourceForge, download available from http://starnetastro.com/

Yes, I was reading something the other day about one of my other interests (motorcycle racing): the article said that when motorcycle racing got going seriously in the 1950s, they were recording top speeds of around 130mph with 60hp. Since then, engine power output in MotoGP has increased by 600-and-something percent, but top speeds have only increased by 60-ish percent (that's not to say that 220mph isn't plenty fast enough on 2 wheels!!)

We discussed this (briefly) a little while ago:

Perhaps not relevant because I bought mine last year, but it took 3 or 4 months to arrive. Maybe check in with the retailer, see if they know anything?

Don't we all!! 😁