DRT

Glad to hear it worked out. I bought a batch of the 45mm ones because I wanted to use them on a range of sizes of scope (8", 12" and 16") and agree you could get away with the sorter ones for an 8". Happy collimation

PLEASE DO NOT REPEAT THIS UNLESS YOU KNOW EXACTLY WHAT YOU ARE DOING AND UNDER NO CIRCUMSTANCES LOOK INTO OR STAND BEHIND A TELESCOPE THAT IS POINTED AT THE SUN WITHOUT A PROPER SOLAR FILTER IN PLACE ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ I just tried a quick experiment with my TV Pronto and a 2" Baader UV/IR Cut filter. First I set-up the scope with the filter in place on the nose of a 2" diagonal and placed a loosely fitting sheet of paper across the eyepiece end of the diagonal. I then pointed the scope at the sun and a small, very bright disk was projected onto the paper. I left it in place for a few minutes and then slewed the scope away from the sun and removed the sheet of paper. It wasn't remotely warm. I then removed the UV/IR filter and repeated the experiment. 15 seconds in this happened... I quickly ended the experiment My conclusion is that the UV/IR Cut filter certainly rejects a significant amount of energy/heat. That and Daystar's recommendation to use one is good enough for me

I can confirm that the nose of my Quark is never hot when I finish a session but I can also confirm that I have burned a hole through the centre of the lens cap when I forgot to remove it I hope the sun comes out tomorrow as I'm itching to test some of this stuff

Thanks for your post, Neil - very informative! Can I ask how you are testing whether or not the beam behind the 35nm Ha filter is cool?

I did, and it has been replaced, but the problem was with the exit window just before the eyepiece and Daystar declared it to be "a known issue" rather than damage from mis-use. I suppose I'll know if the new one develops the same problem but I suspect if Daystar thought that was the issue they would not have replaced it. I think the key to this is the diagonal, which never gets even remotely warm and suggests to me that harmful UV and IR rays are not getting past the filter. If it isn't reaching the diagonal, it can't reach the Quark.

I understand where you are coming from. My choice to use the UV/IR Cut filter is based on two things: (1) the generally accepted view seems to be that energy rejection is required to protect the Quark (not my eyesight) and (2) given that the risk associated with the UV/IR Cut filter relates to potential damage to the OTA I am happy not to spend twice the price of the OTA on a front-mounted 150mm ERF. As I said at the beginning of all of this, I have been using this set-up for some time and have never noticed any problem with heat in either the OTA or the diagonal. I'm happy with the set-up and I get great views so my intention is to stick with what works.

But Daystar also have this on their website, which advises that refractor users can use a UV/IR Cut filter instead of a front mounted ERF: http://www.daystarfilters.com/inout_article_base/index.php?page=view/article/4/UVIR-Cut-Filter-application-for-Refractors I do understand the difference between the two - I am simply trying to establish what is required versus what is ideal. Those two things are very different and come at vastly different cost.

That's not what it says. It says you need an ERF above 80mm - it doesn't say it needs to be aperture mounted. The only advice I can find on the Daystar website is that when an ERF is required you can fit a UV/IR Cut filter to the nose of your diagonal as an alternative to a front mounted ERF. I can't find any aperture limit where that advice would no longer apply.

I agree with that. The consistent message across the variable advice from retailers is that an internal ERF can harm your OTA if the light beam is off axis. Mounting a 2" filter to the nose of a well fitting diagonal and a good quality focuser prevents that from happening and the UV and IR go straight back out the way they came into the tube without reaching focus and without touching the sides.

I don't think it is clear. The advice on the various sites is different so my instinct tells me to go with what is published by Daystar. These two pages lead me to believe that I don't need a front mounted ERF... Daystar Quark Flyer http://www.daystarfilters.com/inout_article_base/index.php?page=view/article/4/UVIR-Cut-Filter-application-for-Refractors

I just read that S@N article. There is a much more detailed description on the Altair Astro website but much of that seems to be the opinion of the retailer rather than advice from Daystar. Is it just a coincidence that Altair also sell all of the ERF options mentioned?

I wouldn't bet on that Where did you see the over 3" advice?

I have seen that written on some retailer's websites but the Daystar spec doesn't mention any aperture limitations. What is does say is that you should use a UV/IR Cut ERF on the front of your diagonal if using a tracking mount.

I'm sure I read somewhere that the main reason for blocking UV before the Quark is to protect the Quark, not your eyes. Adding the UV filter to the eyepiece would mean that the full dose of UV would enter the Quark. I use the Baader UV/IR 2" on the nose of my diagonal in my Altair 152 F5.9 and have never noticed any problem with heat in either the OTA or diagonal.

@FLO - it might be worthwhile stocking some of these alongside the Berlebach M10 to 3/8ths adapters as some tripods might just need a replacement bolt to do the job

According to the manual the port on the mount is RJ-12

I have just placed my order, Steve. Thanks for getting them into stock so quickly

Another tip: when replacing the collimation bolts make sure you replace them one at a time so that the secondary mirror does not become loose. Remove one hex bolt and then replace with one of the new ones and screw in until you start to feel resistance from the secondary, then move on to the second one and repeat the process until all three new bolts are in place. You should then find that the secondary hasn't moved very far and collimation should be quite easy to achieve with just a few small adjustments

As one Scotsman to another, the one's I linked to are identical to Bob's Knobs but about 1/3rd of the price ?

Hi, I use these bolts on my Newtonians as they are much easier to adjust than having to use an Allen key... http://www.wdsltd.co.uk/product/3338/adjusting-screw-steel-metric-wds-605/ You need the M4 45mm long version - part number 605-200445 Derek

It's an LED torch ?

Tomorrow I head for the Galloway coast with the hope of some dark skies. My travel kit consists of an Ercole mount on a Berlebach tripod and this lot... ...and a Quark and a box of bits and bobs. Slumming it in the south of Scotland ?

I have just had my first look through the repaired Quark and it is fantastic! The surface detail is much more pronounced than it was before and I haven't spotted any dull zones in the FOV. I am convinced this is effectively a new device attached to the original Barlow section and I must say I am delighted with the outcome. Phew! ?

You're not wrong, mate. I think I've had the Lunt out about three times since the Quark was sent off. Guaranteed sunshine for the rest of the summer ?

Less than two months after agreeing to help resolve the problem Widescreen Centre returned my Quark to me today. Daystar have not supplied any information about what the fault was, how it occurred or what they did to fix it but it looks to me that they have replaced the entire red section of the device. It is a slightly darker colour than I remember and absolutely no signs of use. The service from Simon at Widescreen Centre has been excellent and I am quite impressed that Daystar turned this around relatively quickly during the period leading up the the total eclipse in the USA. It is a sunny day tomorrow so I will be testing it out and will report back