Newtonian Spider

[Tandum]

Who else sells secondary spider cells apart from protostar?
I'm looking for a big one, 4".

[coldlegs]

This mob make a lot of interesting secondaries.

http://www.1800destiny.com/Merchant2/merchant.mvc

Cheers
Stephen

[Tandum]

Cheers steve but I don't think a curved spider can support a 4" mirror.

[barx1963]

Robin
Astrosystems ( astrosystems.biz ) sell spiders, secondary holders, secondary mirrors etc. I have just received a new mirror and holder from them as well as a little self contained dew heater for the secondary that runs on a 9v battery. All well made, thought the holder uses a 4 point collimation setup that is a little different. I believe Peter Read at SDM uses these holders.

Malcolm

[Tandum]

Cheers Malcolm, these popped up in google for me late last night. They certainly look to be the right price, I'll take a closer look when I can get some more computer time at home. Robin

[barx1963]

Astrosystems is a scary website, you could end up spending a lot of money there.

Malcolm

[rmuhlack]

Teleskop-Express?

http://www.teleskop-express.de/shop/index.php/cat/c64_Selbstbau-----mechanische-Teile.html

[Tandum]

Thanks for the links guys. I've ordered a holder and spider from Astrosystems.

[ausastronomer]

Hi Robin,

Just wondering what your issues were about buying a Protostar secondary holder and spider? I can only assume it was cost, or a worry about the delivery time?

I have an Astrosystems secondary holder and spider on my 18" Obsession with the optional secondary mirror dew heater. I have Protostar heated secondary holders and spiders on my 14" and 10" scopes. Without question the Protostar units are far better quality units than the Astrosystems. Better built, better designed, better materials. That having been said the Protostar units are the absolute Rolls Royce and the Astrosystems units work just fine. With the Astrosystems units you need to let the scope top end air dry properly after a heavy dew. In a damp environment the collimation bolts/center bolt can get a corrosion build up making it hard to adjust/remove. My 18" accidently got exposed to a damp environment (my fault) and I had to spend a good couple of hours getting all the bolts undone and reconditioning the threads so I could adjust it properly. To be honest at one point in time I thought I had ended up with a solid stuck one piece non adjustable, non removable secondary assembly. That having been said the conditions the UCA was exposed to shouldn't have affected the secondary holder how it did. The UCA's on the other 2 scopes were still in as new pristine condition. Because so much of the US population lives inland many of them have no clue about designing/building things with corrosion prevention in mind. I live less than 1km from the ocean and use stainless steel wherever/whenever possible.

Cheers,
John B

[Tandum]

Two things swayed me John. Cost and the holder. I have them making a holder for this GSO mirror now and I can simply get another holder made when I change to a 4" mirror. Changing secondary mirrors now was not in the budget. This scope will live in a foam dome, I don't get dew issues in there, in fact I've never had to run a dew heater in there at all. But thanks for the heads up. If I ever jam it in the car and get it out of dodge I'll keep that in mind.