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.