Jump to content

Banner.jpg.b83b14cd4142fe10848741bb2a14c66b.jpg

Dangerous PST on eBay?

moriniboy

By moriniboy
in The Astro Lounge

Recommended Posts

  • Replies 39
  • Created
  • Last Reply
malc-c

malc-c

Posted
Posted

No they don't, but without the ethalon it is useless and possably dangerous.

Could you explain what this is and how it makes the scope dangerous - is it something that could be resolved fairly cheaply ?

Link to comment
Share on other sites
moriniboy

moriniboy

Posted
  • Author
Posted

I'm not sure what part the etalon plays in making the scope safe to use, I thought it is only used to tune wavelengths so you can observe prominences etc but I may be wrong.

As its an F10 scope the removal of the etalon also affects where the scope comes to focus, a further complication.

Essentially the scope as it stands IMHO is all but useless unless you need a spare black box or objective lens

The etalon can not be bought separately as far as I'm aware.

Link to comment
Share on other sites
Astrobits

Astrobits

Posted
Posted

The Etalon is an interference module that transmits the chosen wavelength and rejects all others. It is essentially the primary filter and without it the telescope is nothing more than a normal refractor ( assuming that all other bits are there, which I doubt if the Etalon has been removed ). Dangerous if someone tries to look at the Sun with it.

Nigel

Link to comment
Share on other sites
trazor

trazor

Posted
Posted

How can you tell from the pictures that the Etaon is missing, or is this down to the fact no eyepieces are provided and this Etaon is the eyepiece with filters built in ?

Carefully check the scope to the picture on the box.

You will notice a piece missing, between the tube and the black block.

Link to comment
Share on other sites
malc-c

malc-c

Posted
Posted

Ahh.. looking at the larger picture it does look quite "manky" around where the tube enters the black box area.

God some poor bu99er is going to be disappointed when they get it home... let alone the chance of having their eyesight permenatly damaged as I guess this will now have no filtering whatsoever, let alone Ha filtering ?

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted

I've found out recently that the etalon cuts out a large range of frequencies, but there's also an ERF in the bottom of the eyepiece holder and a very narrow passband filter between that and the eyepiece. I don't think it's likely to damage someone's eyesight, but it's not going to work as an Ha telescope either.

James

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted

Could you explain what this is and how it makes the scope dangerous - is it something that could be resolved fairly cheaply ?

As explained to me the other day, the etalon is a sort of filter that allows a passband of about 0.7 Angstrom (1A = 0.1nm) every 10A. The remaining filters chop out all of the wavelengths away from the Hydrogen alpha emission line. It's possibly the one part of the scope without which it cannot be made to function in some way and is pretty much irreplaceable without getting hold of one from a second PST.

James

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted

I wonder if it is the remains of a PST that has been used as a stage 2 mod donor. Perhaps not by the vendor. I guess it's entirely possible they did get it in a charity shop (and that it may not have arrived there from the person who removed the etalon), weren't able to get it to work and are selling it on, but knowing that it cannot work as they now surely must before the auction ends I think it would be less than decent not to close the auction and restart it as "not functioning, parts missing, spares only".

James

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted

The price of a second-hand working PST, I reckon :)

I've never seen an etalon for sale on its own. I'm not sure if it was the new or old model PST (I suspect it was the newer model), but if it was the old model and the objective was rusty you'd probably have to consider at least a stage 1 mod (assuming you could find an etalon). If it is the newer model and the mini-ERF had failed then you might be able to do a stage 1 mod if you could find something to cut the longer wavelength IR (if it's an issue). Assuming of course you could find an etalon.

If it were offered up as spares only then without good pictures or descriptions of the filters and objective it might well be scrap at any price. If it's a new model and the mini-ERF and blocking filter are genuinely in good nick and you happen to be looking for one (as I was recently) or want one for a spare then those may be worth paying for. I'm not sure the rest has any value at all.

James

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted

Presumably, a PST with the etalon removed is pretty worthless. And fairly dangerous?

Depends on whether the mini-ERF held up or not, I think. And for how long for. I'm not sure it would be immediately dangerous, but the additional heat might mean the ERF suffered.

James

Link to comment
Share on other sites
allcart

allcart

Posted
Posted

well i thought id put it out there, just in case any one wanted to buy it an fix it at least we know it will cost the price of another PST to do up :)

Was it actually you that was selling it Gareth, or were you just joking.

Etalons on there own a as rare as hens teeth.

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.