Collimating a Celestron Nexstar 6se/8se using a Star

hey guys so a little bit of an impromptu video here but I was out trying to do some Imaging for a Venus series that I'm trying to get for y'all and I saw this and that is emblematic of bad collimation so we're gonna have a quick little video on how to culminate a Schmidt cast grain so like next star 6se 8sc kind of thing with some of the Stars so let's hop into it all right so first thing we're gonna do as always is get our alignment done for this I'm just gonna get one star line because I'm gonna star hopping tonight but custom sight all of those location information should be correct central USA we're good it is zero zero eight twenty Rockefeller am yeah savings oh six oh seven two three good and I'm going to be using Vega really bright star you want to select a really bright star for this initial uh testing with this so let's just salute over to bats okay and now that we are on target but out of focus on Vega and that was a good opportunity to explain what exactly call Mission air is and what's causing that kind of issue that we're seeing within our Imaging so our OTA our Optical system right now with our SCT is composed of two different mirrors as well as a character plate but two different mirrors primarily there's your primary mirror in the back but there's also your secondary mirror in the front if we look at the scope right here you can see that primary mirror in the back in our little obstruction here in the front this front mounting spot here secures the mirror and the adjustment that we can do to this mirror is based on three three different screws okay so there's three screws now the proper next question is how do we know which one to adjust and the answer to that is actually that I'm just going to take my hand and stick it in front of the telescope just radially towards one of those screws on the end you can see my finger jutting into the frame right there so that's one screw coming out to the top side there another screw coming to the bottom and then a final screw come in kind of over on that side so that final screw that I just touched is associated with that little shorter area there so we're probably going to adjust that since it should be the easiest to get us back into centering you can think of this very much like centering a bubble level when you're just setting up your telescope initially we just want this to be perfectly equal on all sides so I'm gonna start taking my handy dandy pocket knife screwdriver and making some small tiny adjustments to that and incrementally looking at that make an adjustment looking at that make an adjustment coming back and forth and back and forth until we have something that I think is nice and Center I do want to note right now that I do have a Barlow in place in my Optical train with the camera because the issues with collimation are most pronounced whenever you're at high magnification so if you're going to use multiple Barlow lenses or a Barlow lens for your planetary observations for example then you want to be using something similar whenever you're doing your collimation checks so let's do some iterations and hop to that so now I've got my setup here so I can quickly adjust in live time to see what exactly our feedback is going to be so I'm just going to make a small turn with this guy oh loosen it just a smidge actually loosen it just a little bit come look back looks like we're still off by a bit and just rinse and repeat loosen it by just as soon as okay and now after just a couple iterations I think we're at something that looks quite a bit better Things Are a bit more uniform probably not perfect but I do not have a Batten off mask a bat knob mask is the thing that you'd use after this if you had it to confirm alignment but instead what we're going to do here is we're actually just going to try and focus in on this star and see what shape it has that's looking good so far look at that guy nice and concentric and going further in still looking good let's pull the folk or the exposure back a little bit zoom in a little bit more seems seems fairly alright this does get a bit touchy since we're at high focal lengths but stuff looks dramatically improved from before so that's how we do it that is how you check your collimation and on one final related note you guys might have seen when I stuck my hand in front of the telescope there was a bunch of distortion that came along with it and that was actually because the heat from my hand was disrupting the uniformity of the air and changing the density of some of it around it which thermal variations like that are why we normally give the telescope a lot of time to cool down or acclimate to the temperature before we actually start taking our like serious Imaging for at least planetarium things that are at high magnification but you can actually use this effect to visualize some pretty neat stuff like the heat coming off your hand or dripping off of a cold object or even the pressure variations from Ultrasonics can be really cool it's called schlier in imaging but that's all I've got for you guys today so I hope that was informative and thanks for watching

Channel: Kyle McCaslin

Views: 8,185

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Id: 9iTRuEtFCR0

Length: 6min 58sec (418 seconds)

Published: Sun Jun 11 2023