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First real session w/ the Z8

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#1 MotaGryz

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Posted 23 January 2022 - 04:57 AM

Thanks all for the warm welcome and comments on my first light post from last week. The skies, the dew point, and the kids all cooperated tonight so I could finally make it out for my first successful DSO session, so it's time for another report!

 

I've been trying to soak up as many views of Jupiter as I can get, since it's getting awfully close to disappearing from any reasonable observation around me for a handful of months, and this way it'll be extra fun to revisit it when 1) it's darker, 2) the planet is in opposition, and 3) experience improves my seeing. I only got 20-30 minutes/night with it from my backyard, but I figure it'll pay dividends to put in a lot of early reps. It was good to go through the routine of getting the scope out there, line everything up, align the finderscope, collimate, allow it to acclimate, navigate to the planet, focus the low power eyepiece, switch to the higher power pieces without moving the scope (this is taking more practice than I expected). The sooner all of this becomes totally natural the sooner these nights will get that much more enjoyable.

 

The Z8 went out mid afternoon today so I could get everything set up for both a Jupiter session before dinner and a DSO session later in the evening. Jupiter wasn't great tonight -- it appeared like something above a fire with wavy distortions even at 80x power. ClearDarkSky had seeing as below average, and tonight did seem to be the worst focus I've had of the planet in the four times viewing it so far. BUT -- the skies were clear and the forecast favorable, so I went inside feeling pretty good about my chances for the evening.

 

I went back out around 20:30 and was immediately blasted by my (south) neighbor's backyard LED lights. They are a LOT. I don't know this neighbor well (just moved into the neighborhood six months ago, and unlike where I grew up there isn't a whole lot of social interaction among neighbors here), but I decided I'd try to stroll over there and make a nice request. We had a nice little chat and he seemed to agree to turning off the lights so I walked back to my backyard feeling pretty good about things. Strangely, about five minutes later, about 25% of the lights went off but the remainder stayed on blasting. I chose not to press my luck further this evening and will continue to fight that battle another night. Boy are they rough though... it's difficult to look up from the eyepiece without the night vision getting pretty crushed. I may need to develop some additional strategies here.

 

I started the evening with the Pleiades b/c why not? It's easy to find and looks beautiful through the 30mm (40x). I think it gives about a 1.7° fov, and I think something like 2° might just be that much better. But tonight wasn't about something I could do in binoculars... it was time to try out a few of the challenges I had planned for the evening.

 

First on my list was Eta Cas. It took me longer than perhaps I'd like to admit to navigate the scope even to a place where I was confident that I was looking in the right constellation. Eventually I got slightly frustrated so I did what I probably should've done in the first place which was grab the binoculars. With these I was able to confidently locate Navi, and I spent a minute studying the patterns of fainter stars between there and Eta. Back to the finderscope, and within a few minutes I finally had it centered on what I was reasonably sure was Eta Cas. I looked at it at low power and didn't believe I was resolving anything yet, but more on that later. I still felt it was the right star, so I swapped in the 15mm (80x) and BOOM: I saw a bigger brighter yellow and then a companion that looked reddish. At the time I was at the eyepiece, I had forgotten what colors things were supposed to be, so I was really hoping that this was what was to be expected (I looked back at TLAO between the session and writing this). I spent some time at 80x and then at 133x, and just enjoyed the satisfaction of my first observed double.

 

Next on my list was Almach. This one was certainly easier for me to find in the scope than Eta Cas, since it seemed to greatly outshine anything within a few degrees of it. This time when I looked with low power I was reasonably confident I could resolve the double, so I bumped it to 80x and put on a nice big smile on my way to the eyepiece feeling pretty good that I had found it. After focusing I could see a bigger brighter yellow-ish star again but this time with a beautiful blue companion!

 

With the scope on Almach and my eye on Algol, I figured I'd go after M34. I failed. Tried a couple of times but was struggling to see anything in the finder that could be an open cluster, and I also am just not good yet about tracing a line from point A to point B in the sky with any reasonable accuracy. In any case, the first few stops of the night took a bit longer than I expected, and Orion was now in view for me so I decided to move on and try again another night.

 

What can I even say about M42? It was spectacular. I could resolve the trapezium (four anyway) even at low power, and was pleasantly surprised at the level of shading (of various grays) I got from the nebula. It was the first of what will be many nights spent swapping out magnifications and slowly poking around the nebula. I found a nice little equilateral triangle of similar magnitude stars to be strangely satisfying.

 

There was one stop remaining for the night, but Sirius wasn't in my 20° wide window to the southern sky yet, so I decided to revisit M45 b/c why not?? Once Sirius did pop into view, though, it was time to go after M41. This time I grabbed the binoculars first and was surprised at how easily I could locate the fuzzy patch. After pretty easily finding this one in the finderscope, it hit me just how helpful it was at this stage in the game to do my spotting first with the binoculars to get a feel for the neighborhood I'm going to be hopping through.

 

M41 was lovely -- I saw a nice mix of contrasting yellow and blue stars. The color difference was on the fainter side, and most definitely looked better to me at the lowest power, so I spent quite a bit of time looking around the eyepiece with the nice 2" 30mm.

 

It had been a little over an hour and a half at this point, and I felt pretty good about the night. I decided to navigate to Almach one more time for practice, and got there more quickly this time. I took one more quick peek through the low power eyepiece just to ensure I was on the right star, and then smiled one last time and packed up.

 

So we're off to a good start here and I'm having a blast. A couple of firsts tonight, but let's just list them all for completeness:

- First moon, check (Luna, then four more a few hours later!)

- First planet, check (Jupiter)

- First double, check (Eta Cas and Almach for dessert)

- First open cluster that doesn't rhyme with Three'a'deez, check (M41)

 

As far as general observational notes, there are a few. First, I'm not comfortable at the finder or the eyepiece yet. I don't have the right chair or the right posture or even have figured out the best place for my legs when I want to settle in for a longer look. Next, the laser collimator that came with the Z8 seems like it's kinda a mess. When I rotate it in the eyepiece, the dot on the primary makes a circle a little bigger than the center circle on the mirror, so that was a little disconcerting. I do plan on learning how to collimate the laser collimator, but admittedly my initial goal was to get good at collimation without using a laser. A 2" cheshire is actually on its way so I can begin my education next week. We can talk about all that in a post of its own when I spend some time with it and have something to report.

 

I appreciated how many people seemed to actually make it through my lengthy first post. My plan was to actually cut back a little on this one, but that seems like it went about as well as my hunt for M34. Thanks in particular to clearwaterdave, JohnBear, Dave Mitsky, Ulmer Spatz and I'm sure I'm missing others for some tips and tricks in the first light thread that helped me to have even more fun tonight!


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#2 sevenofnine

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Posted 23 January 2022 - 02:57 PM

Welcome to C/N! welcome.gif

Nice report!! Seems like you are well on your way or this isn't your first rodeo? Neighbors with lights can really test your patience can't they. One thing I've learned is to be as quiet as a mouse during set-up. Very often when my neighbors hear me bump something...all the lights come on and stay on sigh2.gif

 

I wouldn't sweat getting collimation perfect on an 8" f/6 Dob. They are pretty forgiving in their views. I can't tell the difference anyway. Most of the time I just check the collimation cap and if it's close then out the door I go. What does help though is a good astronomy specific chair. They are pricey but worth it IMO. The most popular are Starbound and Vestil. They are the perch type that have the most adjustment. I have the TeleVue Air Chair that is like a drummer's stool but designed for astronomy. It is less adjustable but fine for your Dob. The very comfortable and swiveling seat is pneumatically adjustable. meditation.gif



#3 SteveG

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Posted 23 January 2022 - 03:44 PM

 

As far as general observational notes, there are a few. First, I'm not comfortable at the finder or the eyepiece yet. I don't have the right chair or the right posture or even have figured out the best place for my legs when I want to settle in for a longer look. Next, the laser collimator that came with the Z8 seems like it's kinda a mess. When I rotate it in the eyepiece, the dot on the primary makes a circle a little bigger than the center circle on the mirror, so that was a little disconcerting. I do plan on learning how to collimate the laser collimator, but admittedly my initial goal was to get good at collimation without using a laser. A 2" cheshire is actually on its way so I can begin my education next week. We can talk about all that in a post of its own when I spend some time with it and have something to report.

 

I appreciated how many people seemed to actually make it through my lengthy first post. My plan was to actually cut back a little on this one, but that seems like it went about as well as my hunt for M34. Thanks in particular to clearwaterdave, JohnBear, Dave Mitsky, Ulmer Spatz and I'm sure I'm missing others for some tips and tricks in the first light thread

Which 2" cheshire? Be advised that a true cheshire will not work to collimate your focuser axis (what the laser does), also known as secondary tilt. Do you have a collimating cap?


Edited by SteveG, 23 January 2022 - 03:45 PM.


#4 MotaGryz

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Posted 23 January 2022 - 03:57 PM

Which 2" cheshire? Be advised that a true cheshire will not work to collimate your focuser axis (what the laser does), also known as secondary tilt. Do you have a collimating cap?

A buddy of mine from across the country offered to ship me out his 2" Farpoint cheshire for just the cost of shipping, so that is what is on its way and should arrive this week.

 

I do not yet have a collimation cap and also was poking around for one of those. I did find the Rigel cap that seems to be recommended available online... is that worth grabbing?



#5 MotaGryz

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Posted 23 January 2022 - 04:05 PM

Welcome to C/N! welcome.gif

Nice report!! Seems like you are well on your way or this isn't your first rodeo? Neighbors with lights can really test your patience can't they. One thing I've learned is to be as quiet as a mouse during set-up. Very often when my neighbors hear me bump something...all the lights come on and stay on sigh2.gif

 

I wouldn't sweat getting collimation perfect on an 8" f/6 Dob. They are pretty forgiving in their views. I can't tell the difference anyway. Most of the time I just check the collimation cap and if it's close then out the door I go. What does help though is a good astronomy specific chair. They are pricey but worth it IMO. The most popular are Starbound and Vestil. They are the perch type that have the most adjustment. I have the TeleVue Air Chair that is like a drummer's stool but designed for astronomy. It is less adjustable but fine for your Dob. The very comfortable and swiveling seat is pneumatically adjustable. meditation.gif

Thanks, Seven (can I call you Seven? :-P)

 

It is indeed my first rodeo with a telescope, but I am a long time naked eye observer and lover of the night sky. I haven't been sweating collimation too badly -- I am fully aware that it's not perfect at the moment but also fully aware that I'm loving the views anyway! The day will come when I get a chance to meet up with some folks from a local club (or CN!) and really learn to get it a bit better, but for now I'm happy as a clam.



#6 SteveG

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Posted 23 January 2022 - 07:29 PM

A buddy of mine from across the country offered to ship me out his 2" Farpoint cheshire for just the cost of shipping, so that is what is on its way and should arrive this week.

 

I do not yet have a collimation cap and also was poking around for one of those. I did find the Rigel cap that seems to be recommended available online... is that worth grabbing?

Okay - you are getting a true cheshire. Good, and you don't need a cap! That cheshire will get your primary axis (tilt) to a very high level of precision, as long as you use it with a calibrated primary center spot.

 

The problem here is you don't have tool for your focuser axis (secondary tilt). Until you can get that laser squared away. IMO, you should buy the Farpoint laser. They are excellent, and fit your 2" focuser with no slop at all.

 

I prefer Seven of Nine.  Jklol.gif


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#7 MotaGryz

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Posted 23 January 2022 - 07:54 PM

Okay - you are getting a true cheshire. Good, and you don't need a cap! That cheshire will get your primary axis (tilt) to a very high level of precision, as long as you use it with a calibrated primary center spot.

 

The problem here is you don't have tool for your focuser axis (secondary tilt). Until you can get that laser squared away. IMO, you should buy the Farpoint laser. They are excellent, and fit your 2" focuser with no slop at all.

 

I prefer Seven of Nine.  Jklol.gif

Out of curiosity, is there a tool other than a laser that can help with secondary tilt? I've read a handful of posts that seem to imply it's nice to not have to ever rely on a laser, but it's not clear to me how you get the secondary tilt right without one.

 

Those Farpoint lasers are expensive, but I did get the cheshire for practically free so perhaps it's worth the investment.



#8 Waynosworld

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Posted 23 January 2022 - 09:06 PM

You really need to use your laser, so it is out of collimation itself, the cheap ones I have collimated myself, but I have come to the conclusion that it is luck to get them dead on, and the only way as far as I am concerned is to have it dead on when spinning it is from at least 10 feet away which is luck.

 

You already have it so what will it hurt to try to collimate it, it is not doing you any good being unused, so build a little holder using 4 round headed screws in a piece of plywood evenly spaced apart 2/3rds the length of the collimator that rides on a smooth surface all the way around the barrel, then put a block as a backstop on one end so it does not move forward or backward when spinning it, I then put a piece of newspaper over my computer tower and point the holder/laser at the newspaper that is resting against the face of the computer tower at least 10 feet away, I use my kitchen countertop end and a c-clamp to hold the collimator base solid where it does not move.

 

I spin the collimator and see how bad it is, then I use an allen wrench to see what adjustment screw does what, as in my opinion they do not appear to do what one would think they would do, normally on the cheap ones I just loosen all three and then start turning each one a little and if it goes the wrong way I put it back and turn another one, I keep doing this over and over until I fail or succeed, I have had it take more than an hour to succeed starting over and over, I have done this with around 4 cheap collimators, after I dropped one and knocked it out of collimation I gave up and bought a Farpoint from Don at EyepiecesEct, it works like a laser and collimation cap even though it might not be made to replace the collimation cap, I just center the return beam on where the beam is coming from and call it good, I recently found a used Glatter laser in the Cloudy Nights Classifieds with all the little bits for everything and that laser confirmed the collimation.

 

This is what I made to collimate my collimators.

 

DSC00170.JPG

 

DSC00171.JPG

 

Another thing I would stress is that the focuser can be sloppy, if you collimate it and then remove the laser and then put it back in and things are different you might have an issue, I now have nice focusers also, Starlight, and two Moonlites, I do not have them issues anymore, not all focusers are bad, but mine were either sloppy or single speed.


Edited by Waynosworld, 23 January 2022 - 09:20 PM.

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#9 MotaGryz

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Posted 23 January 2022 - 10:19 PM

You really need to use your laser, so it is out of collimation itself, the cheap ones I have collimated myself, but I have come to the conclusion that it is luck to get them dead on, and the only way as far as I am concerned is to have it dead on when spinning it is from at least 10 feet away which is luck.

 

You already have it so what will it hurt to try to collimate it, it is not doing you any good being unused

Fair enough, thanks. I guess I'm just one of those aging grumps that tends to look for the lowest tech solution and learn that first. Ya just never know when a battery will die, etc, so it seemed worth the trouble of digging a bit. If a collimated laser and a precise cheshire are the right two tools for the job, then that will do just fine. :)

 

Thanks for the pics and explanation on laser collimation -- I appreciate how clever and helpful the folks here are.



#10 Waynosworld

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Posted 23 January 2022 - 11:26 PM

Fair enough, thanks. I guess I'm just one of those aging grumps that tends to look for the lowest tech solution and learn that first. Ya just never know when a battery will die, etc, so it seemed worth the trouble of digging a bit. If a collimated laser and a precise cheshire are the right two tools for the job, then that will do just fine. smile.gif

 

Thanks for the pics and explanation on laser collimation -- I appreciate how clever and helpful the folks here are.

I am one of the aging grumps like you that bought the cheap lasers, the first one I bought was good/collimated, I used it for quite a while before it started to not work(contacts inside??) in all the bright positions, so I bought another and it was not collimated and I fixed it, the Apertura one I got with the 10" scope I bought was garbage, it was way off, I dropped it again later and had to collimate it a second time, and then the cap holding the battery in jammed, I figure it will be good spot for the cats to chase around until the battery dies and I will throw it away as it got dropped yet again.

 

Getting the secondary tilted properly is easy with a laser and you can likely get it close enough for visual with what you have, if you play around with it and can spin it and have it follow the donut instead of being in the center, if it follows the donut all the way around you likely have it as good as I can get mine, then a collimation cap is all you need to put  the black dot in the center of the donut, when I started I used a 35mm film container with a hole in the center as a collimation cap, by the way the black dot is the pupil of your eye.

 

The thing is once you know how to collimate it with a laser and collimation cap, then you can check your collimation with a laser and barlow, once you have that down without even thinking about it you will start to understand everything and only then with help from experts you might be able to understand what the experts are saying and be able collimate the scope without a laser using more primitive tools, but understanding what the experts are saying can be frustrating when you do not speak French, I believe the experts use lasers but I do not know that.


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#11 Starman1

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Posted 23 January 2022 - 11:34 PM

A buddy of mine from across the country offered to ship me out his 2" Farpoint cheshire for just the cost of shipping, so that is what is on its way and should arrive this week.

I do not yet have a collimation cap and also was poking around for one of those. I did find the Rigel cap that seems to be recommended available online... is that worth grabbing?

A collimation cap duplicates the cheshire.
You need to collimate the laser to achieve good secondary mirror collimation since the cheshire is for primary mirror collimation.
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#12 Starman1

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Posted 23 January 2022 - 11:39 PM

Out of curiosity, is there a tool other than a laser that can help with secondary tilt? I've read a handful of posts that seem to imply it's nice to not have to ever rely on a laser, but it's not clear to me how you get the secondary tilt right without one.

Those Farpoint lasers are expensive, but I did get the cheshire for practically free so perhaps it's worth the investment.

Yes, it's called a sight tube with a pupil at one end and crosshairs at the other. Some companies combine that with a cheshire in one tool and call it a combination tool or collimation eyepiece.
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#13 SteveG

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Posted 24 January 2022 - 02:29 AM

Out of curiosity, is there a tool other than a laser that can help with secondary tilt? I've read a handful of posts that seem to imply it's nice to not have to ever rely on a laser, but it's not clear to me how you get the secondary tilt right without one.

 

Those Farpoint lasers are expensive, but I did get the cheshire for practically free so perhaps it's worth the investment.

As Don noted, a site tube with crosshairs. Some of these are sold as “Cheshire eyepiece”, or collimating eyepiece. 

They are good to have, because you can use the bottom edge of the tool to perfectly center your secondary under the focuser. I still use them myself, even though I have the Farpoint tools. It’s great when all of your collimating tools agree with each other. 


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