Hi I appreciate my use of an ED Barlow and at F30 with a PST Etalon was not optimum but I could see as much detail as in Pedros image with a tad more contrast. I am retired and cannot justify a 180mm+ DERF and a Baader Telecentric Barlow to just observe optimally a few days a year. People image at F...

Hi At F28 you can remove the collimating lens from the front of the PST as its near enough to F-Infinity, or F40 for a air spaced etalon. The re-focusing lens will just about preserve the back focus from the PST. On a 127mm F7.5 with 2x ED Barlow element before PST with Collimating lens at the front...

Thanks.

Hi

Whats the design back focal position of the Baader 1.25x Glasspath to give that magnification?

Rod tested 2x Barlows at -200mm and they actually gave 4x.

Have you measured the image size without and with the Glasspath?

Andrew.

Hi Merlin,

I had a good look but cant find it.

Transmissions from memory were in the range 60-40%.

Andrew

Hi I now can use some bits for a 12" dobsonian. I lent the mirror to someone and they cleaned it without asking and took half the aluminium off! 'Home' aluminised at my first club and some pre-cleaning artefact in the coating it looked like. So might as well take it all off. Whats the best narrow ba...

Hi Are you using a 2" red filter as an internal ERF? My friend used one and forgot to check after adding a Barlow and cracked a red filter. Still useable though as not at focus and seemed to have clear cover glass holding it together. There are various Solar discussions on CN. A review of front DERF...

Hi There was a test of front mounted DERFs in CN and they pass quiet a lot of light into the telescope. Roughly convert a 6" to a 4" in terms of thermal load. You are better masking in front of the objective to get the required F10 for the PST. Silver reflective front. This stops unwanted light heat...

Hi I had a brief try on Thursday. Achieved focus with the PST collimating lens moved forward. All my 2" extensions and a 2" nosepiece was enough. 2" Baader 35nm as ERF. Just had Bobs filter 1 of two held loosely in a Celestron/Skywatcher moon filter holder. Tuned in OK. Two nice large prominences. B...

Hi We had a nice sunny day yesterday. So I had the Vixen mod out. Last time I tried various options including polarisers to try to improve the images. As I was out over the day I had to move the diagonal round for a best field and there did seem to be some benefit from 'clocking' the PST etalon with...

Hi Graphed out the PST, assuming 18mm clear aperture AKA Daystar and 2mm round 10mm Sun for prominences. The Moon filter front which turned up from somewhere at 16mm was exactly right to go after Bobs Comb Filter so explains why it nicely darkened the field. Need my two Chinese cheap Moon filter bod...

Hi With the moved forward primary to reach focus even with the PST Collimating lens moved forward will result in some primary vignetting. The best case is for the Lunt 110mm DERF to be in a 100mm diameter aperture cell. Using Mel Bertles Newtonian secondary field illuminator calculator: Mirror 100mm...

Hi First time copied the first picture a few times, and perhaps twice the second or one 'in the system'. Had two days out in the sun with the PST 'Combat' etalon. Followed by the Re-focusing lens in a Celestron Moon filter in a BF 48mm to 28.5mm adapter infront of a diagonal. The diagonal contains o...

Hi

The first picture is duplicated somehow but they are all there with the captions displaced underneath.

Andrew

Hi I am confused by the image inclusion here. The baffle over the secondary: P1050426.JPG The baffle from the front. P1050427.JPG The baffle refitted with Sika sealant. P1050433.JPG A baffle for the primary baffle made out of a cheap Barlow nosepiece from Rods bits box. P1050438.JPG Mounted as far f...

Hi Well theory and practice may not differ so much. Many people run Telecentric Daystars at F16 to F20 for seeing when F30 is optimum for the telecentric. How did you measure the temperature? A thermometer in the beam? The Baader will reflect most of the energy outside of its 35nm passband, and let ...

Hi

If its a cheap scope you cut cut ventilating holes in the tube above the internal DERF.

With some shading baffle over for skylight.

Andrew.

Hi, Does the PST with the original black box on the back reach focus on the C8? If so how far is the eyepiece field stop back from the C8? The optimum back focus on the C8 for no spherical abberation is 5" 127mm. The PST Collimator needs to be 200mm inside the original telescopes focus to collimate ...

Hi Some pictures of the mod. The baffle over the secondary: P1050426.JPG It seems to repeat this image even though the attachment names are different. I used Cut and Pase which gave me a little box underneath where I said paste inline where I was. ??? As you can see the edges of the correction lense...

Hi Mark,

Can I post photo here of kit few MB ro do I need to load into a photo site?

Andrew

Hi Had a session though windy and almost no proms so nothing to see really. When AstroRod borrowed my laser pointed remote thermometer his highest reading from the 6" Zeiss with internal ERFs was 24C looking into the eyepiece. He bought a UV meter and that showed lower readings up the eyepiece than ...

Hi I have moved the PST Collimator lenses out of the Etalon. I have put a tilted Omega Bobs 40nm ERF in place of the Collimator lens. This works up tp 127mm in my experience, though I have a tilted 2" Baader 35nm futher up the focusser with a 48 mm to 43mm step down ring as a baffle in front. And I ...

Hi Tried the Omega Bobs 1.5A filter as a replacement Comb Blocker. I first tried on the Vixen VMC110 and with the filter well tilted to get its features out of field I got the proms with the PST tuner further round than normal. Had to move to a prtable mount the get a glimpse in the 127mm over a tre...

Hi

More playing about the Revelation extension tube does screw into the AOK Swiss PST front adapter, the Black2 paint making it tight.

Andrew.

Hi I have been trying to mount the PST Etalon in a 2" focusser, with the Collimator lens in a 1.25" barlow nosepiece suspended inside and a 2" extension on the front for a possible 2" ERF or just an extra baffle for the Sun cone. Photos to come. The Revelation 2" extension threads onto a Guan Sheng ...