dan_adi

I would go for the triplet. Neither is top of the line, so might as well get better colour correction

Both are very good mounts. With the 10M mount you could go unguided if you pair it with a refractor. If the mount is in a permanent obsy, you will have to build a model once or twice a year provided that you don't change anything in your setup. Also because 10M tracks in DEC you don't have to stress about polar alignment either, the model will take care of it. So what scope will you use?

SCTs do one thing well, driving people nuts 😆

Finally got to finish the master Luminance at 203 hours on the Abell 2218 galaxy cluster. Still undecided if to add colour data, but it would be cool to reach 270-ish hours like the first Hubble Deep Field. Data was gathered over the summer of 2021,2022,2023. The best images of the cluster I found on Abin was Mortens and Howards. The image is on astrobin: Abell cluster Thanks for looking!

Very nicely done 👍 You can always add more data later, in between other projects.

A little experiment using photometric filters for pretty pictures. Turned out to be a decent image, mostly limited by my processing skills The link to astrobin https://astrob.in/z4pz2q/C/

It's a great mount. Mine is 6 years old I think. Recently got a 10M 2000 HPS because I couldn't help myself :)) I did compare the mean eccentricity between the 10M and the Mesu and the difference is small in favour of 10M, kind of and unguided vs guided comparison. In fairly good seeing and good guiding the Mesu goes head to head with the top brands for sure and at almost half the price. A good mount!

Had a similar problem way back. After unparking the mount started skewing on its own with no input from me or other software. The motors went to blinky. The problem was a loose wire in the sitech II controller. Never liked the idea of the wires being exposed to the elements but what can you do ... Most likely it's a controller problem

Quite wright, If I take the V band mag from Simbad v = 2.02 and scale the spectra at that amplitude, and then convolve the synthetic filter with the scaled spectra, I get the same mag as the input. sp2 = Spextrum.from_arrays(waves=wave,flux=flux, flux_unit='FLAM').scale_to_magnitude(amplitude=2.02 * u.mag,filter_curve="./filters_ascii/johnson_V.dat") sp2.plot(flux_unit='FLAM') Plot Returned magnitude with V filter observation: v2= sp2.get_magnitude(filter_curve="./filters_ascii/johnson_V.dat", system_name="Vega") #output 2.02 mag So that means the color index only provides information about temperature, but not brightness. Makes sense distance is a factor in brightness, besides temperature.

Returns this when plotted: But I do understand what you're saying. The b-v colour index I got from Simbad, I thought it encodes the intensity as well. Hmm, seems harder than I thought. I'm thinking of trying the other way around for fun, simulate the spectrum, then search the V band mag in Simbad, then scale the spectrum to that magnitude, then make a synthetic observation with the V filter and see if I get the same magnitude as Simbad. Scaling to the magnitude would basically underline your idea about brightness

Hello Vlaiv, It is a theoretical exercise in synphot - python I make a source spectrum object that takes as argument Temperature [k] like this: sp = SourceSpectrum(BlackBodyNorm1D, temperature=bv.bv2T(0.60)) bv2T is a method in the bv object that returns temperature having b-v colour index as argument. I retrieve the wavelength and spectral flux density as arrays (and make unit conversion for flux): wave = sp.waveset flux = sp(wave).to(u.erg / u.s / u.angstrom/u.cm**2,equivalencies=u.spectral_density(wave)) then I make the same spectrum but with spextra library because it is easier to work with: sp = Spextrum.from_arrays(waves=wave,flux=flux) Next I make an observation using the V filter (it convolves the spectra and filter): integrated_flux= sp.get_flux(filter_curve="./filters_ascii/johnson_V.dat") # result is 4.737e-15 erg/s/cm2/A Also I get the magnitude easily: V = sp.get_magnitude(filter_curve="./filters_ascii/johnson_V.dat", system_name="Vega") # returns 14.69 # the mag V in a Simbad search is around 2.2 Given the difference I assumed I am actually computing instrumental mags, and I need a zero point for conversion to calibrated mags.

Thanks Andrew seems to be what I'm looking for, but where do I find these equations? are they specific for a given catalog? I am referring to eq. B=B0 -13.028 - 0.01(B0 - V0) etc

Hi, I used the b-v colour index of Polaris to determine temperature. I fitted a back body spectrum for that temperature. All done using astropy, synphot, spextra libraries in python. Easy, but when I continue a make an observation with a V filter, I get an estimated V mag of 14.69, that is way off. The b-v colour index is 0.6, the temperature is 5967.54 K. The flux through the simulated V filter is 4.737E-15 erg/s/cm2/AA It think it has something to do instrumental vs calibrated mags? So basically what is the process to get the mags from an observed spectra?

Not a good idea to integrate the computer in the mount. Can you easily change it when it breaks?.. because it will

I have only one, an 8 inch refractor.

This autumn project. Gathered 74 hours Luminance and 20 hours with the Sloan i'. Next season in full colours with Sloan g' and r' added to i'. So for now only mono Lum data. Looks promising with some extensive IFN. ARP 319 - Astrobin

This is a work in progress. Just ~40 hours of luminance data of ARP 319 region I applied background removal, BXT, NXT, GHS. Don't know if its too many steps or to few but I like the result. Probably over did it with GHS but I wanted to see how much IFN there is

OAG for everything.

I went even deeper. I kept very short usb cables that connect to a USB->UTP converter. I also placed a small 12V Network Switch on the scope. This way everything is connected via ethernet connections. I don't keep a computer in the observatory or on the scope. One data cable and one power cable needed. Through ethernet I never have connection issues. For mobile use it's another story, but for an observatory there no need to place computers on telescopes

That is one big telescope! With the 10M 2000 hPS was the weight problematic or the shear size of the scope and the impact of the wind?

Well, oversampling will unnecessary increase the exposure time and will lower the systems entendue. Depending on how many clear nights you have this could be a problem or not. From the point of view of a telescopes entendue if I compare my 8 inch refractor operating at 0.93 "/pixel to a C11 SCT operating at 0.42 "/pixel, the refractor is 3.57x better. If the C11 would be operating at bin x2, 0.84"/pixel, then the SCT would be 1.1x better than the 8 inch frac. If I wanted to keep the resolution for the C11 at 0.42"/pixel and have a bigger entendue than the frac, then I would need an SCT with roughly 400 mm mirror ... If you are aiming for resolution, those small pixels need to be coupled with a big mirror in order to compensate for the loss of flux at pixel level. And to make matters worse, the lower the plate scale the better the mount you'll need, because at 0.42"/pixel any guiding error bigger than that will increase your FWHM, and defeat your original purpose of high resolution imaging. For my setup If I where to image at 0.42"/pixels I would need a mount capable at sustaining <= 0.2" guiding RMS, that means 10M, ASA, Planewave $$$

Oversampling means small pixels, and, depending on FL, small plate-scale. The only issue with oversampling is that light is spread over many pixels, and this will lower the signal/pixel. This translates into more imaging time for the same desired SNR compared to an optimal sampling. This is important because you are unnecessarily increasing exposure time. As an example for my setup, a chosen target with 23 surface mag (M33), a camera with 6 um pixels, plate scale 0.93, and a desired SNR of 40: total exposure time: 22 hours for Luminance, 97 hours B, 86 hours V, 80 hours R Same setup but sensor with 3.76 um pixels and a plate scale of 0.58: total exposure time: 36 hours for Luminance, 134 hours B, 133 hours V, 120 hours R So you see, simply changing the pixel size has a considerable impact of exposure time

An honest impression ... and perhaps a little bad luck? The main thing is, many people praise this or that company but as in your case, everyone can screw things up a little. Nobody has 100% track record, neither 10M, or AP, or etc. I don't have any of these mounts, but I am curious about the absolute encoder tech on these mounts. Currently I use a Mesu 200, that is 5 years old, and although it took me some time to learn the controller software, I can always happily guide at 0.2-0.3" RMS, and never had a mechanical problem. As an opposite example, there is a fellow mostly active on CN, that had a bad time with a Mesu, and always discourages others into buying the mount. I find it very awkward because most of Mesu users didn't have his problems, and we are happy with our mounts. From what info I've gathered mostly in private messaging with owners of 10M mounts, most of them, especially above 1000 mm focal length or using an SCT, do guide these mounts. To my surprise I even found fellow astronomers on the ASA forum that get better results with guiding. So I always wondered what is the point of paying for the encoders if, in the end, the best results are achieved by superimposing guiding corrections. Off course the guiding corrections are fewer, but still ... If the main reason for purchase is quality craftsmanship then I fully understand, but most seem to be hypnotised by this unguided nirvana. This could be the reason why AP offers the mach 2 with encoders, the masses seek unguided imaging. From time to time, I am highly temped to replace my Mesu with a 10M 2000 HPS, but if I am getting the same 0.2-0.3"RMS unguided, it will have no impact on my images, worse still, if I have to guide for the same RMS, then I've paid 15K euros for the performance of my current 6K mount. Sorry for the long rambling ...

Mesu not CEM120, Mesu doesn't have backlash, doesn't have gears or belts, doesn't need maintenance.

They look like a cool Mesu :). Good to see more adoption of the friction drive. I also like they made a protective case for the motors, I'm always afraid I'll accidentally hit the motors on the mesu. Looking at the guiding graphs the performance is equal to the Mesu, that's great. Also I've noticed they recommend lower aggression and longer pause between guiding exposures, and this is what I also noticed with the mesu. Things settle down quite nice if I use 8 sec exposures and a couple of seconds delay