Quark v Lunt 60 DS (12/10/14)

[SkyGibbon]

It may be the Aptina sensors. I have a Celestron Burst and an ASI 120SS mono and both show the NRs. They both use the exact same sensor. My sony CCDs (dmk21, Skyris 445m and 274m) do not exhibit none of these and I haven't heard of the Sony cmos sensors doing this. Could be wrong though.

Great shots Dr. Robin. Will be able to do some DS 60/Quark comparisons this weekend. Already got the DS 60. Quark will be here Thursday.

The test will be on an SW ED-80 and a Stellarvue ED 110.

Question for anyone. Will I need an ERF for the 110?

[Davey-T]

Thanks for that comparison Robin, been trying to do one myself but since the Quark appeared the Sun disappeared, now all you've done is make me think about getting a TEC140 

Dave

[DrRobin]

It may be the Aptina sensors. I have a Celestron Burst and an ASI 120SS mono and both show the NRs. They both use the exact same sensor. My sony CCDs (dmk21, Skyris 445m and 274m) do not exhibit none of these and I haven't heard of the Sony cmos sensors doing this. Could be wrong though.

Great shots Dr. Robin. Will be able to do some DS 60/Quark comparisons this weekend. Already got the DS 60. Quark will be here Thursday.

The test will be on an SW ED-80 and a Stellarvue ED 110.

Question for anyone. Will I need an ERF for the 110?

According to the Daystar website Quark manual you can use an UV/IR filter up to 120mm aperture, so your 110mm is fine.

[DrRobin]

In one of my earlier posts, I realised that rotating the Quark seems to alter the tuning and speculated that the Etalon was tilted.  It turns out it is.  There is a new link on their website which details some 'quality' issues and the Etalon is deliberately tilted to compensate for droop in Crayford focusers.  As I understand it introducing tilt and then compensating with tuning will lead to a higher bandwidth and it looks like the tuning knob should be facing forwards to achieve best results.  I will need to deal with my un-even field (also discussed in the link) by rotating the camera.

http://www.daystarfilters.com/Quark/QuarkUniformity.shtml

There is also some very interesting information about the performance, it seems that some Quarks will be better than others as they aim to make them all at least 'Standard Grade' but some will achieve 'Professional Grade'.  You are just going to have to take pot luck on which you get.  This sounds very similar to the good old PST.  Many components which are 'mass produced' are done this way, graded after manufacture with the pro-series cherry picked on test and a premium price put on them.  With the Quark they don't do the cherry picking, so some get a 0.5A filter and some get a 0.3A filter, there is just no way of telling until it arrives.

I think mine is closer to the 0.5A end than the 0.3A end and the un-even field also suggest this, again nearer the SE rather than the PE.  Still it is still in spec and capable of great results.

They also set out their returns policy, well worth a read I think.

Robin

[DrRobin]

Sorry, just an update, tilt causes 'blue shift' and in a Quark it is compensated for by turning the knob clockwise which raises the temperature.  Increased temperature causes 'red shift'.  Red shift is lower frequency, longer wavelength and things going away from us appear better in red shift.

Surface features will always be coming towards us, (filaments) and therefore show up better with a small amount of blue shift (counter-clockwise tuning).

Hope these posts help.

Robin

[SkyGibbon]

Absolutely. Thanks, and I will post any nuances I may find over the next few weeks.

[DrRobin]

Absolutely. Thanks, and I will post any nuances I may find over the next few weeks.

Great, it will be good to get another Quark v Lunt 60 DS shoot out.  Lets hope you get a Quark that is nearer the PE grade than the SE grade and you will notice higher performance than your Lunt 60 DS on the close ups.

And if you could send a little of the Nevada sunshine our way that would be great.

Robin

[SkyGibbon]

Hopefully, as that is the reason for the purchase (closeups) and being able to use it on almost all my scopes.

I can't complain this week on the weather. September was tough. A few tropical storm remnants came through and wrecked most weekends.

Summer was even tougher. I just can't get into solar viewing or filming when it is 40 - 45c everyday. But, it is getting nice. 27c day, 20c at night, 15% humidity, no clouds......all week. I love October here.

[Montana]

Davey-T don't even think about using a Quark on a TEC140, the Quark can be used on any refractor except oil spaced objectives. I was told at the IAS never to use it without a full ERF on the front (TEC140), the Quark expels the heat back out the front, he demonstrated when I put my hand there and the objective was very hot, he said the heat could damage an oil spaced lens, so there is no way I would like to test that theory out. However I know someone who has for a short spell and it was OK, but I am not taking that risk.

Alexandra

[michael.h.f.wilkinson]

I think that the key problem is that the heat expelled forwards by a half-size ERF or dielectric UV-IR filter in the tube is focused on the objective, leading to localized heating. This local heating of a comparatively thin layer of oil might even cause it to boil locally, because convection cannot spread the heat out efficiently in liquids in a narrow chamber. The thermal conductivity of solids is much better than that of oil, so temperature differences are evened out much more quickly in the glass than in the oil.

[Davey-T]

Davey-T don't even think about using a Quark on a TEC140, the Quark can be used on any refractor except oil spaced objectives. I was told at the IAS never to use it without a full ERF on the front (TEC140), the Quark expels the heat back out the front, he demonstrated when I put my hand there and the objective was very hot, he said the heat could damage an oil spaced lens, so there is no way I would like to test that theory out. However I know someone who has for a short spell and it was OK, but I am not taking that risk.

Alexandra

Thanks Alexandra, yes I have read about the problems with oil spaced objectives so wouldn't use without front mounted ERF, only joking really as I will be heading for divorce if I spend any more astro money, just ordered a Moonlite focuser for the LS60 so the xxxx will hit the fan when the credit card bill arrives  

Dave 

[michael.h.f.wilkinson]

Thanks Alexandra, yes I have read about the problems with oil spaced objectives so wouldn't use without front mounted ERF, only joking really as I will be heading for divorce if I spend any more astro money, just ordered a Moonlite focuser for the LS60 so the xxxx will hit the fan when the credit card bill arrives

Dave 

Guess why I have a separate credit card and only I see the bills

[smerral]

Great shots and interesting comparison.

[HenryW]

 

 Thats great! 

 

When taking pics trough a Lunt, do you get that color?

[DrRobin]

 

 Thats great! 

 

When taking pics trough a Lunt, do you get that color?

Hi Henry,

Thanks.  Visually images in Ha look deep red as the Ha band is in the red spectrum.  However, we use mono cameras to image in Ha as the Bayer matrix on colour cameras can cause an interference pattern (Newton rings) and there is no light in the green or blue so you waste 2/3rds of the chip.  Colour bleed across the Bayer matrix can also cause blurring.

Some imagers just prefer the mono images (you can generally see more detail) and others like to apply a false colour to the mono images.

I hope that helps.

Robin