With the recent closure of VTC, I had something in mind to start a group which could still offer services a telescope store provides to the residents in the lower mainland. My plan is not to open a shop but to run the program through SFU Starry Nights. I have discussed this idea briefly with the organizer at SFU starry nights and got a positive response regarding this. I have yet to speak to RASC but wanted to see what sort of interest FVAS would have. We would need volunteers who are well informed and can give great advice on DIY projects, equipment purchases and even maintenance tips. I know there is a ton of information online but nothing beats having a face to face interaction.
P.S. I need any tips I could get in cleaning the mirror of a 12" Skywatcher Collapsible Dob. I have not attempted this before and any advice would be greatly appreciated. Also, after cleaning the mirrors do you recommend I do a rough collimation with a Cheshire or a collimating cap? Or just go with the laser method?
Post by Mark McLaughlin on Feb 22, 2017 12:02:23 GMT -8
Seems like a good idea on first thought. Not sure you can get the dedicated staff to run this,if they work only for the joy. Worth a try, I guess.
As for cleaning your mirror..leave it! Unless you really have a dirty mirror cleaning it can only harm it. If it has sap or bird poop, or a big "gob" then, yes do it.The flashlight test only shows the surface dust, and is not really a good way to tell how "dirty" it is. It takes A LOT of dust to impact the view, mainly contrast goes first. Your particular brand is noted for having a "soft" overcoat. Go to Spectrum Coatings.com and see for yourself.
I clean the club 20" and my own when really bad, i mean after going to the Pit for viewing, lots of grit and pollen up there. Use Dawn blue dish soap with a Fox hair brush to gently remove the crud. I use my garden hose! Then rinse with some de-ionized water,like you get at those water refill stops. I blow mine off with a clean air compressor like you find in camera or computer shops. No oil in the air. Lots of videos on the web to show you how, just keep your fingers off the surface, don't use them like in one vid where the "expert' uses his finger to remove a spot. Good luck! MMc
Post by deepskydarrell on Feb 22, 2017 13:36:55 GMT -8
My Truss dob isn't a collapsible one, the secondary cage needs attaching each time.
I use my laser to tweak the Secondary so the beam hits the centre dot on the primary. Then look up from behind the primary through the truss and collimate the Primary so the beam returns back to the laser's cross thatch. That's it for the laser.
Then I drop in the Chessire to fine tune -- I like to shine a white light into the Chessire's side opening and that illuminates the peep view with the primary's centre dot reflection very near the centre of the illuminated peep view. Then tweak the primary's bolts to centre the dot's reflection in the illuminated Chessire's reflection and I'm good to go.
This last bit sounds confusing but is quite easy since with using the white light, only the final centre bits are illuminated and there's no other confusing reflections to see.
So to recap: After lasering,
1) drop in Chessire
2) shine light into side of Chessire
3) tweak primary to center the dot in the little Chessire field.
Hope this helps.
16.5 inch F 5.3 Zambuto Optics homebuilt Dobsonian