Do you think my dew / light shield is long enough?

[cometcatcher]

Only just it seems, to reduce street light glare in the direction of a low comet. I hate street lights. :mad2:

[Dennis]

To minimise the potential of vignetting, I once read about a rule of thumb that suggested the length of the dew shield should be 1 ½ x the diameter of the telescope.:shrug:

Cheers

Dennis

[cometcatcher]

I'll take the vignetting. It has to be this long to block the street light from directly hitting the lens.

[Amaranthus]

So much for a 'shorty' tube mode Kevin!

[cometcatcher]

At least it's not heavy. Now that the street light is beaten, I need one a bit longer to poke through the clouds. About 1Km long should do it. :D

[AG Hybrid]

Have you considered flocking the inside of the scope tube? Also, the inside of the initial/original dewshield? What about flocking the focuser draw tube? You should also check the inside of your diagonal to make sure its either painted flat black or flocked.

I did that to my AR102. Short of shining a torch down the middle. Its pretty much immune to stray light from street lights and nearby homes. I think your dew shield is far too long. Definitely going to have vignetting

[Marios]

Im no expert on the subject perhaps try flaring out the dew shield mid way to open up the FOV.

[cometcatcher]

I would have liked to flare the tube making it conical, but I ran out of time and sticky tape. ;)

If flocking helps I'll give it a try. At the moment as soon as the light hits the lens it's all over red rover. Unfortunately the street light is very close and as good as shining a torch down the tube.

[Marios]

Might I suggest some rocks or perhaps a LP filter to cut out the light.?:lol:

[cometcatcher]

Too high for rocks. I can only hope that one of the many hoons that frequent the corner comes to rest wrapped around the pole, giving a 2 for 1 result. :P

I have decided that the light shield needs to extend to 10Km, after several layers of cloud have moved over. :rolleyes:

I did get a 20 second pic last night of comet 2014 E2, partially obscured by cloud.

[raymo]

You're lucky, I've had one brief opportunity in the last 4.5 weeks, and no
likely opportunities in the foreseeable future, according to the long range
forecast. I wish I only had LP to cope with. Late autumn and winter here
is a complete wash out.[literally]. Even on the occasional clearish night
my gear is all streaming wet within 30 mins.I have to coat everything that's not painted or stainless, with a smear of grease. I forgot to do
it once; went to use it three nights later, and all the mild steel nuts and
bolts were rusty. Most winter nights the humidity is at least 80%, and often higher.
raymo

[cometcatcher]

What we need to do Ray, is with our combined 130 years of experience to make an iSpace Telescope. How hard could it possibly be? ;)

Raining tonight as usual.

[raymo]

Raining here too; 85mm in this area today. I don't have the energy left
to design or construct anything much. Maybe we could campaign to get
manufacturers to fit all stainless nuts and bolts to their mounts; it
wouldn't add much to the cost.
raymo

[IanW]

I'd rather see the cheap sods do some basic engineering and stop using delrin and other horrible plastics as bearing materials.

Also a campaign to bring back the proper terms for the focal plane of various optical configurations, eg: Newtonian focus, Cassegrainian Focus etc.

Stainless steel fittings throught telescopes and please oh large company that has a name similar to an alcoholic drink made with honey, can you please get a real mechanical engineer and stop using work experience kids to design things like the counterweight rail on the new LX600 range. The rail on my 12" is a joke.

I'll kick in my 40 years of ATM experience :thumbsup: