Quark Chromo UV/IR cut

Discussions of using SharpCap for Solar or Lunar Imaging
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nexusjeep
Posts: 293
Joined: Thu Oct 18, 2018 3:01 pm
Location: Gloucestershire

Quark Chromo UV/IR cut

#1

Post by nexusjeep »

Hi
I am looking at getting a Daystar Quark Chromo to give me something to play with in the lighter months and was looking on the Daystar site and they say to use a IR/UV Cut filter above 80mm and then there is a sub note that if the scope is going to be used for regularly solar work then you should always have one.

As I will be only using this electronically I don't really want to have a diagonal in play and am unsure whether there is a filter thread on the Quark, so I am wondering if I purchased a 72mm camera UV/IR cut filter the scope is 72mm if this could be placed in front of the main objective to reflect the UV and IR 700nm+ frequency before it even entered the scope. Does anyone who owns one of these have any thoughts on this.

The filter is a B+W one and is £109 as opposed to an ERF which is over £230.

Cheers
Nick
rjbram
Posts: 3
Joined: Sun Mar 12, 2023 1:34 am

Re: Quark Chromo UV/IR cut

#2

Post by rjbram »

For a 72mm scope, you really don't need a filter, I think.
However, if you call or email the Daystar folks, I think they will give you the best answer. I found their web page was a bit out of date when I emailed them with a similar question.
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admin
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Re: Quark Chromo UV/IR cut

#3

Post by admin »

Hi,

I have a quark and use it with an 81mm scope. I decided to have a 2" UV/IR cut filter even though the decision according to the Daystar information was marginal. The filter is on the 2" nosepiece of the diagonal.

What I can tell you is this...

* You cannot fit a 2" filter to a quark - it has a dual nosepiece for 2" and 1.25" connection, but the 1.25" one sticks out further.
* Not sure if you can fit a 1.25" filter, but I wouldn't suggest it. I believe the reason you are supposed to fit the filter onto the diagonal is because that placement puts the filter several inches away from the point of focus, meaning that the sunlight is not *too* concentrated. The closer you put the filter to the quark itself, the smaller the area the sunlight will be concentrated on, and the more risk of the filter failing.
* The UV/IR cut filter does not massively reduce the energy being delivered to the quark - there is still enough sunlight to melt plastic stuff as I found out when I put my quark into the 2" diagonal and forgot to remove the 1.25" dust cover (image below).
* You will probably need to take flats - quarks seem to often give a slightly uneven image brightness that flats correct. Live flat correction in SharpCap works well for this. A piece of translucent plastic - for example part of a cereal packet inner bag - over the end of the scope does a good job of diffusing the sunlight but not dimming it too much
* The hardest thing with Solar observing is not being able to see the computer screen properly - an electronic focuser and remote desktop to control from an indoor PC or laptop is much easier

cheers,

Robin
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eosman
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Joined: Sun Jun 28, 2020 9:21 pm

Re: Quark Chromo UV/IR cut

#4

Post by eosman »

Hi..nice image..try putting your imaging laptop inside a large cardboard box to give you a dark area...some commercial products are available for this also but this is an easy quick fix.
Regards Les
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admin
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Re: Quark Chromo UV/IR cut

#5

Post by admin »

Hi Les,

yep, the cardboard box trick is a good one, although I still prefer the 'go indoors and remote control the PC option' :) I am even working on designing a remote control motorized flat frame gadget that will allow me to put the flat panel in place and remove it remotely!

cheers,

Robin
eosman
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Joined: Sun Jun 28, 2020 9:21 pm

Re: Quark Chromo UV/IR cut

#6

Post by eosman »

Hi Robin
Sounds a better plan to sit inside and modern automation.
The good thing about outside you can see the clouds and image between them on the not so good days though taking the gear down and inside the hardest job if not blessed with an observatory
With Flats I use a Daystar Flat cap, less light that a plastic cereal bag method but blurs any details out and quite a nice flat, though with slightly longer exposures
Regards Les
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