Newtonian scopes (1 Viewer)

Get a lens in cell. A very good triplet lens cell can be had for a fraction of the cost of a branded telescope. Sorry to hear about the mirror. ||

Paul.

Paul Corfield said:

Get a lens in cell. A very good triplet lens cell can be had for a fraction of the cost of a branded telescope. Sorry to hear about the mirror. ||

Paul.

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Thanks for your condolences, Paul. Do you have any recommendations on where to find a nice apo lens cell? I am waiting to hear from TMB, and APO lens cells seem to be pretty rare on cloudy nights (tons of achro's). I see that teleskop-express has lens sets and that's about the only place I've found.
Thanks in advance
Richard

I haven't seen any for a while but then I haven't been looking. There used to be a seller on ebay doing really nice FPL-53 triplet cells but he hasn't listed any for ages. The price was only a 10th of the price of a scope though which makes me think a cell is the way to go if you can find one.

Paul.

Paul Corfield said:

I haven't seen any for a while but then I haven't been looking. There used to be a seller on ebay doing really nice FPL-53 triplet cells but he hasn't listed any for ages. The price was only a 10th of the price of a scope though which makes me think a cell is the way to go if you can find one.

Paul.

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Damn, I wish I found that seller in time, teleskop express sells their objectives for about 2/3s the price of the complete scope. I'll have to keep searching

I have used a TeleVue NP101, TeleVue 85, TeleVue 76 and the TeleVue 60 All great scopes for birding and for imaging. Also used a Questar 90mm (Mak) also very good. Down side they are not waterproof. I also used a Celestron C-5 and a C-8 (SCT's) they are soft in the daytime both viewing and imaging but are great at night for astronomy and also imaging. I use a Swarovski 80mm HD for most of my viewing and imaging now.

Mike

Richardmg9 said:

I have heard that mirror scopes perform poorly compared to refracting scopes for terrestrial imaging. I would love to see some reflecting scope pictures to illustrate this(or just an explanation). I have heard mirror scopes have bad contrast, but I do not understand why. I understand that the secondary mirror causes image degradation, but as in astrophotography, I would imagine the cheaper photon collected per dollar ratio would still be worth it. Any input/images are greatly appreciated. Happy birding

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If one were to examine the aluminum coating on mirrors, you will see that the structure is shaped like a column. Imagine millions / billions of these columns, all of the surfaces being reflective. This causes scatter and loses contrast. With a refractor, there is still some scatter, but not nearly as bad as a reflector scope. Now if your scope has pure crystalline fluorite, then there will be zero scatter for that fluorite element. TEC telescopes utilizes crystalline fluorite in some of their scopes. Not to be confused with FPL53 ED glass.

Another aspect is the one you mentioned, the secondary obstruction.

But alas, most of the astrophotographers just move the contrast slider a bit more for their high end reflectors. A "fast food" optic like a Celestron or Meade will have many more errors than ones from Astro Physics, TEC, Takahashi, etc. This will also affect the contrast and detail as well.