Jump to content

Banner.jpg.b83b14cd4142fe10848741bb2a14c66b.jpg

Mirrors excited

mdstuart

By mdstuart
in The Astro Lounge

Recommended Posts

mdstuart

mdstuart

Posted
Posted

My mirrors from my 16 inch are excited.

They are off to Stafford tomorrow.

They are a bit apprehensive about the etching process they have heard rumors about.

However they are told that the pain is nothing compared the joy they will feel when they have the Hilux 97% reflective coatings in place.

So the test begins..can I see any difference from a degraded secondary and marked main mirror to ones after Hilux..watch this space. Mag 14.5 to beat.

Wish the mirrors luck..

Mark

Link to comment
Share on other sites
  • Replies 51
  • Created
  • Last Reply
John

John

Posted
Posted

How much additional aperture is needed for a .5 magnitude increase I wonder ?

I've heard that the difference between older standard coatings newly applied Hilux ones is the equivilent of having an additional 2" in aperture ?

Hope it goes well Mark and I'll look forward to reading about the results :smiley:

Link to comment
Share on other sites
estwing

estwing

Posted
Posted

It's something that we have discussed while at various rainy Dobfests and at SWSP on the "ethos night"! Me and steve had M42 in both scopes with the same eyepiece next to each other and there wasn't much in it at all...mine has the hi-lux coatings and steve hasnt, but steve has 2" on me so the scale was slightly different obviously

Link to comment
Share on other sites
HD-AP

HD-AP

Posted
Posted

No!!!!! It's a clear night and my mirrors are at Orion optics!

And when you get them back

It will rain for forty days but more importantly forty nights ,but during this time you will have plenty of time to gaze at the perfect surfaces ,waiting for that clear night to unleash their might . :smiley:  :Envy:

Link to comment
Share on other sites
mdstuart

mdstuart

Posted
  • Author
Posted

Good service so far from Orion. I was made very welcome when I dropped off my mirrors...very efficient booking in service.

Amazing place.I should have stayed longer and looked around.

Confirmation of my order and a welcome letter today...

They have confirmed that high lux coatings might give the equivalent boost of moving from a 16 to nearly an 18 inch mirror so my galaxy count of 800 is going to rise a bit! Earlier in this thread the improvement from high lux was likened to going from an 8 to a 10 inch mirror but of course this is a much bigger jump in % terms than from a 16 to an 18 inch mirror.

They also pointed out improved coatings may highlight optical imperfections that exist before coatings are applied. Let's hope the mirrors on my scope which have been owned and rated highly by two other users on this forum before me turn out well in this regard.

I will of course report back again in due course but it's all going well so far.[emoji3]

Mark

Link to comment
Share on other sites
mdstuart

mdstuart

Posted
  • Author
Posted

An example of the feedback they gave me on the process which might be of interest......

"Without some very clever mechanical set ups, it is very difficult to actually test the reflectance on coated primary mirrors, they just won't fit in spectrophotometers. When we coat our mirrors we use a microscope test slide placed next to your mirror and measure that to get your mirror's reflectance. However, we are able to test the reflectance of most secondary flat mirrors so from that, we can assume that the primary mirrors are coated in a similar manner.

After cleaning, our coating technician tested the secondary from your 'scope and found it to be a relatively flat plot in terms of reflectance from 400 to 700nm which is what your eye detects. The problem though was the actual percentage of reflectance. It was a pretty standard and regular 85%, which at its peak, Hilux offers 12% more. There are further complications here though. If you look at the schematic at the top of this page   http://www.orionoptics.co.uk/OPTICS/ellipticalflats.html you will see that the reflectance of your flat at 45 degrees, it's operating angle, will be reduced further because the actual over coating of the aluminium is in effect, about 40% too thick and that will reduce the performance.

As far as we know, no other manufacturer coats their secondary mirrors differently to the primary mirrors because it is more expensive as you can't coat primary and secondary mirrors together, they have to be coated with different layer thicknesses. Depending on the coating applied, this difference can be in the 2-3% range and is a nett loss in overall reflectivity of the system.

I think you are going to be very pleased when you look through your scope when we have applied Hilux."

Link to comment
Share on other sites
mdstuart

mdstuart

Posted
  • Author
Posted

The mirrors are home...

All re-attached and ready for first light.

7da980382275c2c63aa109742ba24aba.jpg

The package was extremely well packed..my son will enjoy popping bubble wrap for a long time!

The surfaces look like new...not even a hint of the Pinprink holes or marks that were there before. Even the larger ones that had black centres are completely gone..[emoji3] AMAZING job Orion Optics.

So the next stage is first light....I will report back..

I hope this thread will help others who are pondering re-coating..

Mark

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.