Xilman

6 hours ago, Ratlet said:

With things like monolithic sct lenses you can fit a decent focal length in a small box so then all you need is some imaging and communications.

Ay, there's the rub. Fairly ordinary CCDs will provide the imaging; up- and down-links are significantly more expensive.

However, that is not all you need. You need thermal control, precise attitude control, rad-hardened electronics, power supplies ...  All these do not come free.

On 12/06/2022 at 15:04, Astro Noodles said:

I agree, for $1 million I think you start getting into the realms of thinking about doing it. In 20 to 30 years time I'm convinced that an amateur group will have put their own telescope into orbit. Or perhaps a commercial enterprise.

Vintage Micro: The Amateur Space Telescope | Drew Ex Machina

An amateur space telescope? - Free Online Library (thefreelibrary.com)

Certainly attempts to get amateur space telescopes into orbit have failed so far due to a number of technical and cost limitations. But as technology improves and costs come down, I think within a couple of decades someone will have done it. After all - 30 years ago, how many amateurs had access to a telescope with CMOS cameras, powerful laptop computers, advanced stacking and processing software, guiding, wireless, broadband etc ?

Let me put this rather sad image here for SGL people to contemplate.

As some of you know, my observatory is 3km (2 miles) from a volcano which erupted last September through December. I was lucky and had to deal only with ~30cm of ash and no lava.  A guy a very few km south of mine had an observatory with a 50cm and an 80cm telescope. I estimate that the total cost of replacing that kit is in excess of  €1M, itself over $1M.

1 minute ago, Clarkey said:

That's nothing. I did a whole night of luminance data using a blue filter.🤪

Cut your losses and use good data.

Nothing is ever completely useless. If nothing else, it can serve as an awful warning.

In the case in question, I would check to see what else may be in the field. You never know --- you might have a nice image of a passing asteroid.

I never throw away potentially useful data. Even if they are not useful for the intended purpose they may be useful for something else in the future. Storage is cheap.

On 03/06/2022 at 16:25, iapa said:

I have updated Astrodata Shared.xlsxto look neater.

It will also now update the calculations for unity gain and exposure based on selected imaging camera; IF you have Sharpcap Sensor data for your camera.

Added graphs of e/ADU, read noise and dynamic range for selected camera.

 

This looks rather useful. Would you like to receive updates?

I can provide information about Starlight Xpress cameras, for instance, and could also report back a few tyops I discovered in the current version.

Paul

On 08/06/2022 at 10:26, vlaiv said:

No, no, no!

Jpeg data is completely useless.

Format uses 8bit data which clips away most of faint signal that is very important and on top of that - it adds compression algorithm artifacts.

Jpeg was developed to alter image in visually acceptable way so that it compressed better. This alteration of data makes stacking useless as stacking expects "natural" noise and signal distribution in order to work properly.

I would phrase that as "mostly useless".

Completely useless for making a pretty picture and for the reasons given.

Jpeg may clip away some of the faint signal but not always all, especially if the dynamic range in the image is limited. Consequently, stacking will add that small signal and improve the SNR.

The result may be perfectly useful for astrometry of faint objects, asteroids or instance, or for bare detection of very faint objects. The latter can indicate whether an eruptive variable, nova, supernova, etc was above a limiting magnitude at the time of observation. Such detections can be scientifically valuable.

On 27/02/2022 at 05:24, spacegalaxy said:

What's the smallest scope you have own? Also, please include performance and details (Like aperture, focal ratio etc)

Clear nights!

This image on my BAA member's page was taken with a 2.2mm f/1.8 refractor. Although taken by a friend, I own similar equipment myself.

https://britastro.org/observations/observation.php?id=20191209_191900_36b00eba365581f4

(Yes, I know this could be regarded as cheating but nonetheless I own several ~2mm aperture short focus refractors. Apologies too, for the BAA displaying the image sideways. It was upright until the recent revamp of the site. Perhaps I should contact the webmaster.)

11 hours ago, pete_l said:

New types of telescope?

One that comes to mind is amateurs starting to image more in the infra red. Primarily to beat the ever increasing scourge of (visible) light pollution.

To some extent that is happening. I have Sloan i' and z' filters. I also use Sloan r' quite often because it suppresses moonlight (a form of light pollution) and seeing is better in the red and near IR. The major use case for me is multi-band photometry rather than imaging per se.

Never thought of doing tri-colour pretty pictures in those three filters. Thanks for giving me the idea. Perhaps some dusty star forming regions might be appropriate targets? Other suggestions welcomed.

Up above I suggested imaging out to 4 micron or so. That will require detectors not based on silicon.

1 hour ago, Astro Noodles said:

Perhaps in 20 or 30 years from now, some amateurs will have their own space telescopes. 

I don't see why not. Launch costs are way down and falling rapidly. The expensive bit is space-hardening the electronics and paying for the up- and down-links. Young Mr Musk is working on all of those issues.

Diffraction limited optics is what I look forward to. At the moment it is very expensive to have adaptive optics, especially if you also need a laser guide star (not to mention the safety aspects of the latter).  Something which could reverse the seeing motion in software rather than hardware would be wonderful and is not obviously impossible.

Near-IR imaging, to 4 microns say, would open up a whole new field to amateurs.

Medium resolution spectroscopy at a low price (say resolution of 1-5k and a price of £0.5-2k pounds) would be wonderful.

Software correction of distortion in the optical train is something I have been investigating and starting to work on it. It would make large aperture scopes much cheaper. My prototype is a 20cm shaving mirror which is not even approximately parabolic. It cost me about €6 and a web cam at prime focus is another €5. Compare that price with a 20cm Dobsonian mounted Newtonian with eyepiece or camera. Now think of building a 1m mirror, with its lousy optics corrected in software. Should be possible for under £1000 whereas a professionally built scope would be around £1M at that aperture.

No shortage of ideas ...

On 21/05/2022 at 12:23, vlaiv said:

Second reason is if you plan to scale darks or use dark optimization (which is really the same thing except computer trying to figure out proper scale factor).

Sometimes you build dark library of say 10 minute exposures, but for some reason use 5 minute exposures when shooting target - you can still calibrate your light subs with mismatched darks if you scale them.

Dark current signal builds up linearly with time - which means that in 10 minutes it will be twice as strong as in 5 minute exposure, or 5 times as strong as in 2 minute dark exposure.

We can exploit this fact if our camera behaves properly (CCDs tend to behave good for this and CMOS cameras behave poorly - so I would say that this is mostly available for CCDs).

Makes sense?

Makes perfect sense and is exactly the reason I take and use bias frames with my CCD cameras.

My interest is photometry of objects which could be as bright as V=5 or as faint as V=20 --- a million-fold range in intensity. Exposures can range from well under a second to several hours. Most of the time I use 30s subs as that is a good compromise between noise and sensitivity and having to discard images because of cosmic rays, tracking errors, passing clouds, being Starlinked, and so on. In my case, standardizing of 30-second calibration images and scaling appropriately is precisely what I need.

On 02/06/2022 at 21:10, AstroK said:

I have an Altair 183C PRO and during this last week appeared what I can only describe as interference patterns.

Each of my cameras have shown this pattern on (at least one of) flat, dark and bias images. It seems intrinsic to the construction of the camera. Standard pre-processing removes them from the final science images. The image below is a bias from a SBIG-8 in 2x binning mode. It has been heavily stretched to show the fringes and the warm pixels.

What is curious, to me anyway, is that you have only just noticed them on your kit.

On 01/06/2022 at 08:11, ollypenrice said:

Here, even more than in the OP's post, the rings are not only distinguished by brightness but by colour.  Not only that: the colours seem to be organized somewhat like an opened-up white light spectrum. (Or perhaps a sequence of RGB,RGB etc?)

Some might regard this proposal as heretical but here goes. If it is the only data you have there may be no alternative.

Three things (at least) are obvious in your image. The rings are coloured, they are wide and they are circular.

That they are coloured indicates that if you process them, you should treat the R, G and B channels separately: split the image into three, process independently, and recombine at the end.

That the rings are circular indicates that the two-dimensional Fourier transform of the images will show strong symmetrical structure.

That the rings are wide indicates that there will be strong structure at low frequencies in the Fourier transform.

Therefore, try taking the Fourier transform of each image and then zero out all but the strong low-frequency structure. If when you inverse transform the result you end up with broad circles in the same position as the originals, and not much else, you know you have selected the correct Fourier components.  Use that inverse FT image as a flat.

Completely screws any photometric accuracy and may add other artifacts as well, but it will get rid of the aesthetically displeasing rings.

On 02/04/2022 at 14:31, Zummerzet_Leveller said:

Well it turns out keeping things 32bit in Siril has worked.  I've got to redo my flats as they are not correcting properly, probably me playing too much to try different options.

...

Still some vignetting so the flats definitely need redoing IMO.

Looks like my Asperger's strikes again. Oh well.

I'm somebody who is more interested in what people do rather than what they own. Think of it as an odd personality trait.

1 minute ago, Astro Noodles said:

I don't know - you tee it up so a guy can show off his telescope and he tells you to go and look on Wikipedia.

 

Sigh.  Why should I want to show off a design into which I made no input? The "0.4m" is far more significant than "Dilworth" in my opinion.

Anyway, if you wish --- www.astropalma.com and http://www.larrosa.ch/astrooptic.htm if you want to find out more about this particular Dilworth.,

19 minutes ago, Astro Noodles said:

Another question - What on earth is a Dilworth telescope?

Duckduckgo is your friend.

https://duckduckgo.com/?q=dilworth+telescope&t=h_&ia=web

An entirely sensible question which deserves a full answer so that others can also observe these sorts of things. For outer satellites of JSUN head over to https://minorplanetcenter.net/iau/NatSats/NaturalSatellites.html

Select which satellites in which you are interested and enter the date and a range of times around the observation. I used 2021-07-08 00:00 and 10 positions separated by 20 minutes. The site will return the co-ordinates of the satellite at each time.

Prior to that I plate-solved the image (using a local installation of astrometry.net) and displayed it in an image viewer (ds9 in my case) which indicates the position of the cursor as it moves around.

Many other ways are possible (rummaging around the JPL web site is valuable, whether or not you want to find satellites, as is using Aladin) but I leave those as an exercise for the reader.

On 02/06/2022 at 11:04, alecras2345 said:

No i have no setup. it's always cloudy here and there are street lights.    My bedroom window faces south but there are houses all around, i live in a cul de sac.   I don't know what the solution would be to my stargazing problem.   Like i said i want to do it online but i don't know what site to use.     I like reading about the solar system and i was reading the book Planets yesterday and he mentions that Mercury has an elliptical orbit so on one side of the sun it can be very hot but at the other end of its orbit can be very cold.   Brian cox also mentioned that mercury has a spin orbital resinance,  does that mean that mercury spins 3 times for every orbit?   im not sure.     Brian cox also said that venus and mars once had seas and were earth like, but that was when the sun wasn't as hot as it is now .   Something like that.

Ash 

I will be amazed if it is ALWAYS cloudy!

I started out by going into the garden with a pair of binoculars and a pair of eyeballs, sometimes without the binoculars. Naked eye observing can be fun and informative. It is how I became a variable star observer. I estimated the brightness of delta Cephei each clear night and recorded it and the date and time when observed. Some weeks later I plotted the results on graph paper and derived the period of how often it changed. Still have those hand-written observations in a notebook which is pushing fifty years old now.

On 01/06/2022 at 15:13, alecras2345 said:

what about the science in books, do i skip it?

Yup.

Everyone skips "stuff" they do not understand at first reading. This goes equally for researchers working at the bleeding edge of their field as for complete newbies.

I have been at both ends of that spectrum and have personal experience of skipping stuff.

There is always time later to return to stuff you don't understand immediately --- after you have gained experience.

Who says images of small satellites in the outer solar system can't be artistic?

This one was taken with my 0.4m Dilworth telescope. A Dilworth uses several relay lenses in the optical train, each of which scatters a very tiny amount of light. Usually the scattered light is completely undetectable but if a very bright object, Saturn in this case, is just outside the field of view effects like this can be produced when contrast is enhanced. Saturn was about a million times brighter than its satellite Phoebe, which is marked with the cross lines. Phoebe was magnitude 16.6 at the time of observation, 2021-07-08.

Thanks for providing that RAR. It is indeed identical to the one already on the TCS.  Nonetheless, I ran register.bat in an administrator mode CMD; it successfully installed the DLL. The registry entry was already present from an earlier attempt but I verified that it was as specified in the README.txt file.

What is NOT in the README is that one must double-click the LazyFocus.reg file to install extra gubbins in the registry. Once I did that, MaximDL could see the driver!  The SkyX had to be set to use an ASCOM Focus driver and then LazyFocus. Again, it works (though not in TheSky X 64-bit, unsurprisingly).

Thank you very much for your assisstance. Much appreciated. AFAIK I can now start doing astronomy again.

Pal

Thanks. I will try it but it looks very much like a file I already have ...

4 hours ago, Dr_Ju_ju said:

can you connect the hard drive from the old computer to your new one ??  if so it may be possible to copy over the missing dll, register it, then see if it works ....

BTDT, failed miserably. 8-(

A chap at the BAA (britastro.org) has told me of an alternative.  I will try it out and report back.

My old Win 7 box has died. It used lazyfocus.dll to drive the motorized focusser.

The new box has Win 10 Pro and most everything (TheSky, MaximDL, LesveDome, SX cameras, etc) now works after some re-installation and re-configuration.

The focusser steadfastly refuses to be driven by software. The Moonlite PRO ASCOM driver supposedly works as a LazyFocus driver but doesn't. Everything I have tried so far to install the old DLL has failed.

Has anyone managed to get LazyFocus to work under Win 10? If so, how?

Otherwise it looks like new hardware will have to be bought and got working.

Thanks for any help.

Paul

NGC 2340 is the brightest member of a rather nice small cluster of galaxies in Lynx. Most members are either E or S0 with bright condensed nuclei.

The cluster appears not to be very well known, which is rather a shame in my opinion. It contains  IC 458, 459, 460, 461, 463, 464 and 465 --- the latter also known as NGC 2334. --- as well as a number of fainter members.

This image was taken 10 minutes before Xmas Day in 2019 with a 810s unfiltered exposure on a 0.4m Dilworth-Relay.