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First Viewing nights & concerns + Bottom line


kevenh
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Monday 5th Oct: un-boxing & 1st View

During the day outside I unboxed a Nexstar 8SE (25mm EP) and did a course alignment of the red dot finder. I'm using a TalentCell power bank & that worked well.

I planned to leave the scope outside but rain arrived.

In the evening I attempted to setup the scope in the dark.  I misplaced the camping and the OTA fell into the luckily soft lawn. So that's the metal Shell christened 🤔

I did get to see a glorious moon surface. More detail than from my 80EQ firstscope.

 

Evening 2: Tuesday 6th

Mars was tonight's planned view.

I didn't get on with a skylight so did a solar align on Mars.

Compared to my old scope I've made Mars a brighter White disc with some greyed areas.  (25mm & zoom EP)

The worst thing was mars drifted and when I tried Goto the scope went further away.  Looking at my setup I found North America rather than U.K. 🤔

 

Eve 3 Friday 9th

Last night i.used a GPS to add my garden's Long & Lat as well as a time entry using seconds with my iPhone as the visual time aid.

I failed again at the 1st skyalign.  The solar planet align was used again.

Mars was the target and my viewing.

It was a bright disc again but with maybe more obvious slightly darker areas.

Mars drifted again even though the scope's Motors could be heard.

I retired a 3 bright object alignment and this time the Nexstar was happy.

I could choose over planets and Goto back to Mars. It wasn't central in the eyepiece but OK

 

Tl,Dr

How similar to novice backyard astronomers is my early experience?

I am surprised at the drift in a goto.but hope.that I just need to be better at Skyalign.

The focus setup looks good as Mars out of focus is two perfect circles looking like a doughnut. I didn't observe how an OOF star looked.

******   Bottom line, when the scope fell out of the clamp that 1st day, have I damaged it's function and not just good looks? ****** 

****** Is drift a sign of inaccurate alignment? *********

 

ps Not mentioned is my garden is poor for light pollution and with the old scope it became just viewing the moon & Sun I relied on for interest.

Mars did look ok ~2000 we saw a polar cap with the old scope.

Edited by kevenh
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Not sure about the tracking issues but the fall of the optical tube could well have affected the collimation of the optics in the scope even though it fell onto grass.

Contrast of planetary views can go down hill quite fast with SCT's if the collimation is out.

 

 

 

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First advice - do not unclamp the OTA from the mount. I never liked doing this and until I fixed a handle on the side of the tube only ever did it over a carpet with the mount detached from the tripod. It is hard to get a grip on a 9" dia OTA that does not have a handle!

AFAIK you are expected to keep the mount head and OTA as a unit, and unscrew the mount from the tripod if you have to.  If you keep the legs retracted, it is possible to pick up the whole assembly and carry it through a standard doorway.

The mount should track just fine if you get all the GoTo setup right (lat/long, timezone, date format, DST) and remember to complete the procedure by pressing Align (otherwise it will not track).  GoTo tracking can be very good - i.e. keep an object in low-power field for hours.  There are three menu options for tracking rate (siderial, lunar and solar IIRC).   IIRC the date should be in USA format.

You need a proper external +12v supply and a good plug connection, otherwise the mount may misbehave.

Out of focus objects always have a black hole in the middle with these SCTs (because of the central obstruction).  If it does not look symmetrical, check the collimation.

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A very common mistake that affects the tracking of the Mount is to enter the date incorrectly. The Mount requires the date to be entered in US format I.e. month/date/year, so yesterday would have been 10/09/20.

The other common error is to enter the wrong time zone (Universal Time for the UK) and daylight savings settings (“Standard Time” If you enter the time as GMT, or “Daylight Saving” if you enter the time as displayed on your phone, until the clocks next go back).

Tim

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Thank you all for taking the time to respond.

It sounds like I have to persist with the harsh lesson I learned about assembling the mount & OTA on the garage carpet.  NOT the tripod.

As well as watch how I enter date & time values, for the alignment I could take the time two learn the names of two stars for the "Two Star Alignment" method.

For this part of the 6/8SE manual

 Press UNDO to display the names of the three bright objects you aligned to, or press ENTER to accept these three objects for alignment

I have only seen the Hand Controller mention 'custom 1', etc. for my chosen objects.  Never a name. 

I'll look out for real names - maybe when I looked it was for the unsuccessful alignment.

Anyway, it looks like I'll be persisting & not putting the scope back in the box.

Except when I head to the darker skies of campsites....

Thanks again.

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9 hours ago, kevenh said:

Tl,Dr

How similar to novice backyard astronomers is my early experience?

I am surprised at the drift in a goto.but hope.that I just need to be better at Skyalign.

 

Hello Kevenh, apart from dropping the thing, pretty close 🤣 I don't have your scope but the idea is similar. Understanding the goto is all important. I just could not get the thing to goto the same place twice, so at night I set a laser up in the shed, aligned it with the pole star, put a couple of marks down and was then able to play to my hearts content in the shed during the day. Once I vaguely understood polar alignment, 20 or 30 youtube videos later I then sorted the home position of the scope. The next thing I did was put a couple of pins in the shed roof to show where certain stars were at that moment in time and kept on aligning the thing until I had it worked out...... ish. As AstroTim says, date, time and location has to be correct. Get the info from your phone and make a note and check each time as my altitude always needs correcting. Enjoy. Les

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I use either skyalign (choose any 3 bright stars, spread some distance apart, but no need to know their names, and the Mount will try and work out which ones they are and align), or solar system align (not as accurate but ok if looking for easily identifiable or large targets, such as planets). I know a lot of people favour one of the two star methods, but I’ve never tried them so can’t comment. Any of the methods should allow you to accurately track a chosen object for quite some time, at least an hour.

If you search the forum, or web, there will be plenty of guides and tips for improving Goto accuracy with nexstar mounts. Without following the tips the Mount will likely lose some accuracy in it’s alignment every time you slew to a new object, which will be fine if you are only looking at a couple of objects in a given session. You can correct the alignment if that happens but the tips are designed to minimise the need. I happily used the Mount for some time without delving into backlash settings and the like and it might be worth waiting until you are more familiar with the mount before starting to tinker with the config.

 

Tim

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It's always worth spending some time learning the names of "landmark" stars:

  • Merak and Dubhe, the two pointers in the Plough,
  • Polaris - of course - not particularly bright, but the brightest in its area of the sky
  • Mizar (second star from the end of the handle of the Plough)
  • Arcturus - follow the curve of the handle and you'll reach Arcturus,
  • In the Summer, the three stars of the summer Triangle: Deneb, Vega and Altair (lower down)
  • In the Winter, the main stars of Orion (Betelgeuse and Rigel),
  • The Winter hexagon - Arcturus, Capella, Castor, Procyon, Sirius and Rigel.

If you can identify these as they appear in their different times and locations across the year, you will be well on your way to finding alignment without any stress,

Aplogies to those hearing me say this for the umpteenth time, but a great help for finding the suggested stars is to get yourself a 12" Philips Planisphere - it shows the whole visible sky for your time and location in a single view, and has the brighter stars named. Yes, you can get something like this on an app, but I don't think there's anything as effective at showing how the night sky changes hour by hour and month by month, with constellations being visible firstly in the east, then moving west as the hours go by and as the months go by.

 

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+1 for fitting a handle.

This is something I did a couple of days ago because storing my scope means that it has to break into four pieces; the tube, the mount, the counter and the tripod legs.  I can't say I'm happy with handle version 1.1, so it'll have to be replaced with v1.2 when I see suitable materials.

I know the above sounds a pain to sort, but I can get it together fairly quickly in the dark, and the secret to that is practise.  I've only had it a couple of weeks or so, but i spent some time taking it apart and putting it back together in the warm and dry.  I used to be responsible for loaning telescopes to students, and in this respect I'm practising what I preached.

 

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