The Orion Optics AG12 has landed

[strongmanmike (Michael)]

Originally Posted by David Fitz-Henr

Do you intend running the fans whilst you are imaging? If so, then dew should not form inside the tube. Shane from Dream Telescopes has done extensive testing (in a colder climate than ours) and even recommends (for his FAST air system) leaving the fans on permanently for remote observatories as not only does it prevent dew, but keeps the spider webs out as well!

Yes, will try that

Mike

[Bassnut (Fred)]

Originally Posted by David Fitz-Henr

Do you intend running the fans whilst you are imaging? If so, then dew should not form inside the tube. Shane from Dream Telescopes has done extensive testing (in a colder climate than ours) and even recommends (for his FAST air system) leaving the fans on permanently for remote observatories as not only does it prevent dew, but keeps the spider webs out as well!

mmm, thats exactly what I did. In a bit over a year, ALL (OTA, cam, powersupplies, some 7 fans all up) died. Not good for remote Observatories. Its hard, time consuming and expensive to regularly replace every fan.

[strongmanmike (Michael)]

I wouldn't run'em 24/7 (did I mention I had no observatory ) only during imaging sessions.

Mike

[gregbradley]

Also the amount of dust build up on the scope mirror it would cause.

8 months of very part time use has me working out the best way to clean the mirror already.

Greg.

[strongmanmike (Michael)]

Originally Posted by gregbradley

Also the amount of dust build up on the scope mirror it would cause.

8 months of very part time use has me working out the best way to clean the mirror already.

Greg.

Also, according to Orion Optics, the enhanced aluminium HILUX coatings on my mirors have a reflectance of nearly 97% so I can have a lot of dust collect on my mirrors before I am operating at the normal overcoated aluminium level of 91% . I am imagining cleaning the mirrors perhaps once (?) a year..?

MIke

[h0ughy (David)]

Originally Posted by strongmanmike

Also, according to Orion Optics, the enhanced aluminium HILUX coatings on my mirors have a reflectance of nearly 97% so I can have a lot of dust collect on my mirrors before I am operating at the normal overcoated aluminium level of 91% . I am imagining cleaning the mirrors perhaps once (?) a year..?

MIke

lol i remember a certain kookaburra shot that may have you doing that more often Mike

[gregbradley]

Its the windy nights that do the most amount of dust pile up. If clear nights weren't so rare at the moment I would not use the scope on a windy night. And my observatory is very very sheltered.

Greg.

[ericwbenson (Eric)]

Originally Posted by strongmanmike

Also, according to Orion Optics, the enhanced aluminium HILUX coatings on my mirors have a reflectance of nearly 97% so I can have a lot of dust collect on my mirrors before I am operating at the normal overcoated aluminium level of 91% . I am imagining cleaning the mirrors perhaps once (?) a year..?

MIke

Most reflectors (excluding department store scopes) have 96% average reflectivity coatings these days (my >5 yr old C11 and C14 have them), the rarity are large 99% dielectric coated mirrors. But the amount of lost light is actually not a big problem, if that was the case just expose 5% or 10% longer. The contrast loss is the more annoying factor, that can't be fixed by exposing longer.

EB

[strongmanmike (Michael)]

Originally Posted by ericwbenson

Most reflectors (excluding department store scopes) have 96% average reflectivity coatings these days (my >5 yr old C11 and C14 have them), the rarity are large 99% dielectric coated mirrors. But the amount of lost light is actually not a big problem, if that was the case just expose 5% or 10% longer. The contrast loss is the more annoying factor, that can't be fixed by exposing longer.

EB

Hi EB

I am aware many scopes have enhanced coatings these days but it wasn't that long ago that 91% was considered good, I was more trying to make a point that a bit of dust isn't really an issue until it gets to significant levels

Mike

[gregbradley]

Its a judgement call about when to clean mirrors. The normal advice is to not clean it very often. But I have read conflicting reports where a few clean fairly regularly.

Also I imagine dust is harder to remove if its been there for 2 years as opposed to 6 months. It must bake or stick on after a while.

Windy nights are the real enemy here. They can deposit 6 months worth of calm night dust in one night.

Greg.