How do you like that IM615? I was contemplating buying that new from TS as they still have them in stock.
It's quite good compromise for a quick look at moon and planets, bright clusters etc and small enough to take on a weekend away with the family. A Skywatcher /Orion 150mm Maksutov is cheaper and lighter, probably much the same optically so don't think you really have to buy an Intes one from TS.
I acquired mine secondhand and despite its age the optics are pristine and the OTA is cosmetically perfect apart from the usual wear & tear on the dovetail bar.
There are a few issues to be aware of with these scopes:
1. The Intes brackets for finderscopes are unique and compatible brackets are simply impossible to source afterwards. If you do by an Intes mak make very sure a matching finder bracket is included, and ideally an Intes finderscope (or a modern equivalent).
2. Intes supplied a variety of finders and I have seen at least 3-4 variations in the finder brackets.
The finders were either a small 30mm, a tapered 10x50 one like my M615 has, or a straight-tube 10x50 which is on my MK91.
FWIW the 10x50 finders on the M615 and MK91 are both excellent - optically the objectives are good quality coated doublets, fitted with an illuminated engraved glass graticle with across-hair with a clear centre, and the eyepiece is not a stupid one.
However... mechanically these finders - and the matching brackets - are not interchangeable. They are also impossible to find elsewhere, short of making one yourself - though with 3D printing technology or a friend with a CNC machineshop, it's possible to make a nice DIY solution.
3. The Intes OTA has a standard SCT thread on the back (like a C8). To this you need a screw-on adapter for 2" accessories, confirm whether this is included or you buy it separately.
4. The smaller Intes maks - including the M500, M615 and the M715 - shipped in a black padded carry case with a zipped top - as mine did, and the M715 a friend has. Confirm whether this is included as a decent alternative will cost another $100-200.
5. Intes offered two grades of optics - the standard versions were 1/6 wave P-V or better, while the deluxe ones were 1/8 wave or better and a copy of the test result should be provided with the scope. Clarify with the vendor which one is being offered; the deluxe ones do command a higher price.
6. If buying secondhand be very careful concerning the possibility that someone has futzed with it in various ways - such as flocking gone wrong, damaged the focussing mechanism or removing the corrector to mess with the internals of the OTA. While modifications can be done well, they can also be done badly and I have seen examples of that. Also there are scopes that are in a bad way cosmetically, badly handled or dropped, damaging the optics.
7. If someone has taken the corrector off and replaced it, there is the possibility the retaining clips have been over-tightened or the 3 paper shims that separate the glass from the metal cell were lost. In these cases the corrector may be strained, and star images will be noticeably impaired.
The retaining clips should only be finger-tight and the usual method to keep them in place was to apply a dab of optical wax to prevent the screws from loosening, yet easily undone. A dab of nail polish is a good alternative.
If a paper shim is missing it is easily replaced, the material is basically that used for business cards.
8. From about 6 examples I've seen over the years, Intes really did get the moving mirror focussing right - it does not have any kind of mirror slop, though they vary between very free to slightly stiff which may be related to age and how much use they have had. Nevertheless far better than any SCT and I see no reason to put a Crayford on the back of these scopes.
Edited by luxo II, 06 August 2019 - 07:18 AM.