The flocking on the inside of my c14 dew shield is coming adrift and I was considering to replace the flocking material rather than just re-sticking it.
At the same time I want to flock the outside of my 2600mc (I get bad reflections when using the hyperstar). And do you think its actually worth doing the inside the c14 tube as well??
Just wondering if anyone's got an opinion on the best material / supplier? And in particular if you think there's any benefit doing inside the tube (in particular for planetary viewing contrast).
Hi David. For the inside of your c14 you can get flock board from First Light Optics. It may be a bit pricey but you dont have to glue it to your tube. It come as a roll and snaps open against your tube walls. I like the sound of that. Anyway have a look on their site if interested.
Cheers Richard
I'd be nervous about putting anything with out-gassing potential inside my OTA. Richard's advice might make me re-think flocking the interior, though.
I use EVA75 foam (6mm) as a dew shield for my C14 - it's lightweight and naturally matt black. My next move is to re-do it with 1.2m wide foam to insulate the OTA as well (with a one-piece foam roll) in a bid to stop tube currents. Alex (of Astro Shop) has been talking about that for a while, so I figured I'd give it a try. I don't know if that's any use to you.
Dave,
Maybe run the idea of painting the 2600MC black on the ZWO forum
I joined as soon as I bought my 2600MC back in August 2020 and the forum answered most of my questions in a timely manner ( either by ZWO admin or other members , especially Chen , who is the guru of 2600series cameras )
Painting the camera may inhibit some thermodynamic properties ( warming / cooling ??)
Who knows ?
Cheers
Martin
Hi David. For the inside of your c14 you can get flock board from First Light Optics. It may be a bit pricey but you dont have to glue it to your tube. It come as a roll and snaps open against your tube walls. I like the sound of that. Anyway have a look on their site if interested.
Cheers Richard
Thanks Richard- I definitely like the idea of NOT sticking flocking inside the tube. I shudder to think how you’d deal with that if it starts to deteriorate. Cheers
I'd be nervous about putting anything with out-gassing potential inside my OTA. Richard's advice might make me re-think flocking the interior, though.
I use EVA75 foam (6mm) as a dew shield for my C14 - it's lightweight and naturally matt black. My next move is to re-do it with 1.2m wide foam to insulate the OTA as well (with a one-piece foam roll) in a bid to stop tube currents. Alex (of Astro Shop) has been talking about that for a while, so I figured I'd give it a try. I don't know if that's any use to you.
Yes flicking inside makes me a bit nervous too. I’m keen to know if anyone’s found a visible difference with flicking inside? I’ve already got the ota insulated but might look into the foam idea for the shield…
Dave,
Maybe run the idea of painting the 2600MC black on the ZWO forum
I joined as soon as I bought my 2600MC back in August 2020 and the forum answered most of my questions in a timely manner ( either by ZWO admin or other members , especially Chen , who is the guru of 2600series cameras )
Painting the camera may inhibit some thermodynamic properties ( warming / cooling ??)
Who knows ?
Cheers
Martin
Don’t think I’d ever paint the camera. If anything I’d probably make a sleeve to slip over. Got to be very careful not to interfer with the cooling. Cheers
I've been using the Bunnings stuff for several years on multiple dewshields with no problem. My dewshields are made from Coreflute. I cleaned the dewshield section really well, finishing it of with some isopropyl alcohol before applying the stuff. When I'm done for the night I bring everything into my man-cave which has a dehumidifier running to dry everything off.
I emailed the people who make Black 2.0 & Black 3.0 about its water fastness considering an astro specific application. They were very helpful, explaining that neither product is water proof and not water resistant - these paints are not designed for being subjected to water, dew in our case. They are also extremely delicate, meaning they do not take well to being rubbed, finger or otherwise, as this will alter the surface finish that is attained by the drying process. If you are going to use either one of these paints, best only applied to closed surfaces, such as the inside of a Mak or SCT as these are very unlikely to have dew form on the inside of the OTA. Certainly do not use these paints on any surface that will be subjected to dew or movement, such as a dewshield. These are specialist paints designed for a specific purpose, not with astro in consideration.
Yes I think that Bunnings felt will be a very quick and easy solution for the dew shield (maybe even create a slide-on sleeve for the camera with it too).
Regarding the paint the more I think about it I’m not so sure I’m confident enough in my painting abilities to do a good job . That FLO material looks very interesting for the inside of the tube though. I’ll report back…
There is a misconception that "flocking" the inside of an OTA does something to improve contrast. It does bugger all. Another misconception is that it is the fault of there being a secondary mirror/obstruction that is to blame for the reduction of contrast. The for the effects of the secondary mirror to be apparent, it is necessary to eliminate ALL the other sources of unwanted/scattered/reflected light from within the OTA. Only once these have been eliminated will the true extent of the effect of the secondary be apparent. And this is far less than you think.
To get to the nuts and bolts of what is seen as reduced contrast that is often seen in SCT's and other Cats you need to drop the idea that just because some piece of aluminium is anodized to a black colour that it is doing the job you expect - to eliminate reflections. Black anodised aluminium is a terrible material when examined in the way light actually enters the OTA and travels past these components - at shallow angles of incidence. When you look down into the OTA of an SCT with a light source, you will find that there are an extraordinary number of black anodised surfaces that are glowing with reflected & scattered light coming off these. See the first pic below.
It is important to also compare Cats that do have a known level of better contrast in order to see why this is the case. The second pic below shows the inside of an Intes Mak with light being shone at a very similar angle to that in the SCT. You will notice there is a striking difference in the finish of the baffle tube all along its length and that of the secondary obstruction. This Intes is not perfect either, but the different ways that the guts of the scope have been dealt with are now obvious.
Intes Maks are known for having a series of baffle rings down the length of the OTA. Yet there are other Cats and Cassegrains also known for superior contrast and these scopes do not have this series of baffle rings. Yet what they all have in common is the way the baffle tube of the primary and secondary mirrors have been dealt with on the outside AND inside. And what all these scopes and SCT's do have in common is the inside of the tube of the OTA, they are all painted with a flat black - yet it is SCT's that have the contrast issue.
Adding flocking to the inside of the OTA is tinkering along the edges that will gain you bugger all, because the REAL culprit of the reduced contrast has been left totally unaltered.
When I received the 7" Intes Mak, a previous owner had installed a roll of flocking inside the OTA, right over the series of baffle rings! All this was doing was shedding masses of wee black fibres all over the optics and did nothing to improve contrast - this previous owner had no idea about what flocking was actually doing an only created more problems and solved none. I removed this ridiculous addition to the inside of the OTA and contrast was none the worse, but I had a crap-load of black fibres to try to remove.
My current Cat is a 9" Santel Mak. Unlike Intes Maks, this Russian made Made does not have any baffle tubes inside it. The inside of the OTA is just like an SCT. However, the way the baffle tube coming off the primary mirror is made and finished is totally different to that of an SCT, and this is the source of its better contrast. Not too long ago I did a side by side comparison of this 9" Santel Mak with a 10" APM-Wirth Mak. The target object was the Moon. We used the exact same eyepiece and diagonal in both scopes so this was not a factor in what was seen in both scopes. Through the Santel the black of space with the Moon in the FOV looked like a very dark shade of grey, far darker than that provided by an SCT. Through the APM-Wirth, the same black of space WAS BLACK, not some dark shade of grey! When we looked down into each scope with the Moon shining into each scope, we could see the small areas inside the Santel that were the sources of scatter that reduced the contrast, but the APM-Wirth Mak had none of these anywhere along the baffle tube. And neither scope makes use of that series of rings like Intes uses. This APM-Wirth really has that "refractor-like" level of contrast.
Like I said, adding flocking is not doing anything that you think it is achieving. Not by a longshot. You want to actually improve contrast in your scope? Then deal with the true source of internal reflections and light scatter.
I’ve seen that APM scope. It l certainly has exceptional contrast. No flocking. Though on the night I saw it, it had insulation extending out the front as a long dewcap and that probably also helps to keep stray light out.
A properly designed dewshield will help reduce stray light too. Certainly. But what is more critical is how the inside of the OTA is dealt with. A dewshield is token.
Alex that’s a very helpful input thanks for sharing your experience.
So if I’m understanding correctly, if I were to use that matt black 2.0 on the baffle tube (inside & out) and on the secondary mirror holder there should be a noticeable increase in contrast for the imaging/viewing of brighter targets?
This would be quite a challenging project (and a level of risk involved too) but if the results are substantial I’d be very tempted to give it a go
. That FLO material looks very interesting for the inside of the tube though. I’ll report back…
