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  • What sort of scopes would you like to see in the future?

Hi there,

we are considering to add a third system in Namibia. The Veloce will be hopefully operative shortly, and some small issues fixed with the 20" iDK.
We are experiencing sort of a "congestion" on the iDK around new moon, which results in us not being able to gather the data quickly enough (after all, it's only one scope). So the idea of adding another scope was born.

I wanted to ask our users about what their preference would be. Would a smaller scope be okay, or shall we go for another big one? We have a few interesting options, among them one 55cm f2.6 system (!), or simply another AG Optical or Planewave astrograph which work pretty neat. We walue your input on this subject very much 😀

What kind of scope would you like having?

Hi Lukas!

I would like to vote for a large aperture fast astrograph option but the system said "You don't have permission to vote" 🤣

Fernando

Oh, interesting 😅
Could you please retry? It should work now. I forgot to set the correct permissions.

    While I am watching the progress here it seems already to turn out towards the "big, fast" scope. Hehe 🚀

    Well, I have a few options on the table with the respective costs. My favourite would be a 20" Planewave system with a 0.66x reducer. Effectively we'd end up with a resolution of 0.81" per pixel, 2280mm of focal length (f/4.5) and an area covered of about 55'x55'.

    Would this qualify as big and fast?

    Another option would be a very fast 22" f2.6 (!) primary astrograph. The combination with a CMOS like the GSsense4040 (like with an 16803 CCD) would lead to a FOV: 1.46° x 1.46° and a Resolution: 1.28", which is a tad undersampled.

    We could use the QHY600 CMOS with it, leading to a FOV: 1.43° x 0.95° and Resolution: 0.54"/pixel. Pretty close, but with a good sampling here.

    The issue with this second system is the cost: It would end up costing about 60% more than the Planewave, and probabily we would need to raise the hourly rate at least for this one scope. I am also not sure if bigger is always better. Definitively one would need way less total exposure time with the fast system, so that for a given target we would end up with less costs for the users. Also, it would be a dream for all asteroid hunters out there who wish to go very deep.

    Any thoughts about this guys?

    Thanks

    Lukas

    Hi Lukas,

    I am interested to see a 22" f/2.6. I think a reasonable price increase is acceptable. f/2.6 means it is almost 3x faster than a planewave f/4.5 and 7x faster than the 20" iDK if I am doing math correctly. That would effectively shorten the total exposure time for the users and also sub-exposure times so subframes are less prone to error.

    It would be interesting to pair it to something like QHY600 which would have enough resolution to fully utilize the pristine sky, and also allows big prints.

    Chris

    Well, I'm not an expert but I think the Planewave + KAF/Gsense sensor gives a resolution of 0.81", which IMO could be a little undersampled for the superb Namibia sky, we would not be exploting the full potential of that location.

    But, the other option, the very fast 22" with the QHY600 has the same resolution as the IDK 20", 0.53", which seems optimum for a seeing of about 1". The max FOV is of 85', which is 2.3 times the FOV of the IDK 20", giving the possibility of targeting bigger objects. And f2.6, of course!

    So, my preference goes for the very fast 22" f2.6. As previously stated, the higher hourly rate could be compensated with shorter total time expositions.

    By the way, a rotator could be a great addition for the new equipment 😀

    Eduardo

    Hi guys,

    thank you for the considerations. I forgot to add that the new system - no matter what optics - would be mounted on a L-series mount ofrom Planewave, mounted in Alt-Az, thus the optics would be equipped with a rotator (which is needed to track the sky correctly).

    Yes, the f2.6 is appealing, the issue is that it costs about 50% more than the Planewave + reducer combination. I am waiting for a few more offers on the fast optics. Of course, going from 20" to 22" alone is raising the price considerabily 😀

      lukas_demetz

      I don't know much about optics but will it be very difficult to do collimation well on a 22" f2.8 telescope?

        Very difficult. Collimation is not the main issue, but orthogonality is. The whole construction needs to be very sturdy to not create any issues in different positions.

          The more i get informed, the more I want to stay away from the GSense4040 cameras. There is some inherent noise which makes for noisier images than comparable CCDs. Too bad the 16803 is not produced anymore...

            fernandoyang 😣
            The specs would be awesome, but the price 😛

            Another interesting option (on paper) would be the QHY411 (with the IMX411 chip), 14192 x 10640 pixel array with 3.76um pixels. This in combination with the f2.6 system would be simply crazy. Like the costs; the camera alone would cost as much as a complete Planewave 20" system. The filters, which would have to be custom made, cost in the order of about 5000 USD 😅

                15 days later

                Good morning all,
                I am new here your choices seem to relate to systems made for astrophotography, will you also consider opening yourself to scientific observations in the near future? if so, I would be ready to invest money for guaranteed observation time
                jpv

                Hi Jpv,

                could you please elaborate on what kind of scientific observations you would address? Or to be specific, what kind of system you would like to have for that? 😀

                One option has always been to get a system for spectrography... But well, that would be very specific 🙂

                Thanks
                Lukas