The Lazy Astronomer
-
Posts
952 -
Joined
-
Last visited
-
Days Won
1
Content Type
Profiles
Forums
Gallery
Events
Blogs
Posts posted by The Lazy Astronomer
-
-
Follow up: If anyone has any comments on my application of noise exterminator (particularly on the fainter background dust) I'd like to hear them - unsure if I've taken it a step too far or not.
-
I recently downloaded a trail of noise exterminator (which I now completely love!), and went through a reprocess of my bubble image from last year, plus a couple of extras. These are crops from the same SHO stacks - I'll be working on the full image next, although I'm not very good at processing wider field shots, so that may never be finished!!
Approx 12hrs, split equally between Ha, Oiii and Sii.
Let me know your thoughts!
Bubble:
I always get comments on my magenta stars, but I feel they are appropriate in some images (i.e. hubble recreations) - their inclusion in this one is deliberate.
NGC7538:
SH2-159:
I liked the structures in this, but I don't think it stands up too well to zooming into it. I think because it's fainter the other two above, I've pushed it a little too hard.
-
5
-
-
This thread needs more images!! (and a bit less arguing)
If anyone's got a few comparisons of their data with no decon vs blurx vs the best they could do with manual decon (and no other processing) I'd very much like to see it.
I don't necessarily mind doing deconvolution (it's somewhat cathartic, I think - playing around with the settings to try and get it right), but I never feel I've gotten the best out of it, purely due to lack of experience, so BlurX is a tempting prospect.
-
3
-
-
The EU buy/sell pages on here are as option. Not sure how active they are though as this is predominantly a UK forum.
-
I missed this one first time around too. It's an object l really like, and this is a nice rendition. It's on my list to do one day, but l did some test shots on it a while ago and discovered I'd need a 9 panel mosaic to capture the whole thing with my set up - far more of a ballache than I'm willing to undertake at moment!
-
13 hours ago, Priesters said:
I suspect it is pinched optics as this is the first time I’ve used this scope (WO GT81) in such cold weather. Only other change has been a new camera (Altair HyperCam 183C). Is there anything I can do about pinched optics?
A dew heater tight to the lens cell may help. There's probably also some adjustment that could be done, but it's not something I've ever done (or indeed would ever want to do, for fear of messing something up).
Wait to see what the stars are like on a less cold night - it may be that under more normal winter temperatures all is well again. If it's still bothering you after that, I'd look to have a professional sort it out, personally.
-
I don't see square stars, but what I do see is possible evidence of pinched optics. Can happen when the lens cell gets cold and contracts, and as it's been very cold recently, l wouldn't be that surprised if that was the case.
-
1
-
-
Hmm, interesting for sure. I share the same reservations as others around how "real" the sharpening/deconvolving is though - I think it would be nice if something more was made available about what the AI is doing to achieve it.
-
1
-
-
On 04/12/2022 at 09:43, wornish said:
Looks like a serious piece of kit. But, at 33lbs (15KG) the head is just not practical for nightly setup and take down.
If I ever get a permanent site then I would be very tempted.
The head on this is actually lighter than the head of the EQ6-R, which is nightly setup/take down mount for many of us. Granted, the overall package would be heavier when you included tripod and counterweights though.
-
Yep, stars seem to be sitting much more naturally in that one. Maybe for my taste they're a little too prominent, but everyone has their own opinion on how starry images should be!
-
2
-
-
The L-enhance is a narrowband filter, with a bandpass at Ha and another at Oiii & Hb. Narrowband images are false colour (although the HOO combination afforded by these dual/triband filters gives a relatively close approximation of true colour, with Ha mapped to red and Oiii mapped to green and blue), but the fact that most of the light spectrum is not recorded means photometric colour calibration won't give the optimum result.
The heart is quite strong in Ha emission and Oiii is generally much weaker for all objects, so I would say a fairly strong red bias is to be expected.
-
1 hour ago, Icesheet said:
starless + stars' in pixel math.
That'll be the culprit l reckon. A good way I've found is use an unscreening and rescreening technique:
1. Do all your normal processes up to star removal, then duplicate the image and run starnet (or starX, whatever you use) on one, but don't ask for it to make a stars only image.
2. In pixelmath, do:
~((~original)/(~starless))
This will give you your unscreened stars image
3. Process your starless and the unscreened stars images however you desire, then rescreen the stars back in with pixelmath:
~((~starless)*(~stars))
-
1
-
-
A person after my own (lazy) heart!!
Nice dusty region this, and l think l spy (faintly) the soap bubble as well.
What pixelmath did you use to extract and add stars back, they look possibly clipped to me?
-
1
-
-
3 hours ago, nfotis said:
What mount do you have?
I've got the flimsy Nexstar mount the C6 came with, and the eq6r does DSO duties. I'm reluctant to be swapping scopes on the eq6r constantly (plus I'd then have to pick between DSO and planetary on a clear night). I wonder how much weight the little nexstar mount would take... 🤔
-
I'm not sure what's going on here, it could be a NINA or driver problem, but your second image has average and minimum values of 0, which implies your offset is too low. There should not be 0 value pixels even in a dark frame.
-
Thanks for the input everyone! My current planetary scope is a lowly 6" SCT. Hopefully will be able to get something larger for next year, so will take a look at camera options to find something to fit both.
On a related note: is an ADC considered a necessity, or a nice-to-have?
-
It seems like we're in a HGTTG situation here - perhaps I need to start a thread on the right question to ask first 😁
I'll try again: what are people's thoughts on which is the best planetary cam to buy these days? I think the 462mc was generally regarded as a good option previously, but are there any new thoughts on that given the new cameras that have been released in the past few months?
Find a way out of that, @vlaiv 🤣
-
1
-
-
Looking at adding a new planetary camera to my repertoire to allow my 290mm to be dedicated to guiding duties for my DSO imaging.
I'm looking for a OSC, and I'm aware there's been a whole host of new planetary cameras recently released, so, what's the general consensus on the top ones these days?
-
1 hour ago, Elp said:
I think you need to do it if you're going to be changing targets or moving somewhere different in the sky. If you think about it, if you're pointing near the zenith the star field will hardly appear to move, if you point near the celestial equator the stars will appear to move a lot more. Unless the calibration accounts for this you'd have to recalibrate, or at least try adjusting the sidereal rate. To be safe I recalibrate every session on each target.
As per the phd instructions (https://openphdguiding.org/man-dev/Basic_use.htm#Automatic_Calibration)
Because this is a measurement process that is subject to various kinds of mount and atmospheric effects, the most accurate results will be gotten when the scope is pointing within 20 degrees of Dec = 0 (near the celestial equator) and at least 60 degrees above the nearest east/west horizon (i.e. within 2 hours of the celestial meridian). Calibrations can be done in other pointing positions if required by conditions at your site but they will be subject to somewhat more measurement uncertainty. You cannot do calibrations pointing very close to the north or south celestial poles, and the mount must be tracking at the sidereal rate.
-
Sorry, a bit of a thread hijack here, but I think it's relevant.
@vlaiv Speaking of colour calibration, pixinsight has recently gained a new one: spectrphotometry-based colour calibration, which uses star spectra data and camera QE curves and filter transmissions to perform colour calibration. https://pixinsight.com/doc/docs/SPCC/SPCC.html
What are your thoughts on this - is this essentially the approach you've been advocating for for ages, or is it still an imprecise method?
-
You seem to be making the assumption you have a polar alignment problem, but phd is giving you the 3 possible causes and you've discarded the other 2. Personally, I would think PA is the least likely cause unless you've made some recent change to how or where you set up. Like others have said, we need the log to make any conclusions.
-
1
-
-
I often see a Celestron's c9.25 touted as the sweet spot for planetary imaging, but slightly over your budget, and, assuming the equipment in your sig is up to date, a scope that big will lead you to run into issues with mount payload capacity, so I'd think you'd need a scope and mount package.
Coming in bang on your budget is the Celestron 8SE, and I think that would be my recommendation unless you say you already have another mount with a higher payload capacity.
-
As ever Rodd, you are your own worst critic - this is very nice!
-
On 24/11/2022 at 08:06, Andy56 said:
To close this with feedback, the change I made to use Saturation Via Star-profile worked.
I think the multi-star guiding is selected but it only selects one star.
I'll experiment with this on the next clear night.
Many thanks for your assistance.
Andy
Phd2 will only show the guiding cross on one star, but if it's using multi star guiding, it should show circles around 5 - 10ish other stars within the FOV
Image timings?
in Getting Started With Imaging
Posted
Generally, once you've determined an appropriate sub exposure length by the methods mentioned above, there is no need to adjust sub exposure time for different targets using the same equipment from the same location. The only real need to deviate from that would be on targets with a very high dynamic range of brightness (e.g. M42) - in this case, you may also shoot some short exposures specifically to capture the very brightest parts (these areas would most likely have been overexposed with a longer sub).
It should be clarified that this true for total exposure (integration) time, not individual sub exposures. Darker skies would require longer subs to facilitate the swamping of the read noise, but the desired signal to noise ratio would be achieved in less total integration time.