Author Topic: Quick Q after first time out  (Read 347 times)

zajusima

  • Active Astronomer
  • ***
  • Posts: 118
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Quick Q after first time out
« on: December 30, 2017, 06:51:19 AM »
First somewhat clear sky since I got my scope (xt8 classic). I was looking at what I'm 80% certain is Jupiter but with both the 25 mm and 9 mm eyepieces it looks like a white dot with no detail or definitive shape. I was wondering if this is what one should expect. I haven't collimated (sp?) the scope yet ... which I think I have to do ... but all the same I was expecting something more. Not necessarily rings and colors ... but at least a round shape rater that just a brighter white blip than what I saw with the 25 mm lens. Do I need a barlow or stronger eyepiece? The moon looks awesome... however the details are slightly fuzzy.



piatimascomp

  • Active Astronomer
  • ***
  • Posts: 137
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Quick Q after first time out
« Reply #1 on: December 30, 2017, 09:48:28 PM »
So here are my thoughts:

You almost certainly were not looking at Jupiter. Even in binoculars Jupiter looks as a disc and you can make out some moons around it. In an 8" scope you should be able to see plenty of neat detail in the bands of clouds. I suggest getting an app for your phone that does planetarium functionality. There are many which allow you to wave your phone around until it gets calibrated, and then you can hold up your phone in the direction of what you are looking at and it will tell you what it is. You must have been pointing at Regulus or something.
I believe with Dobs you need to check collimation every time you go out. Definitely do this and get your scope collimate
Can you describe better what you mean by the moon being fuzzy? You should use your wider eyepiece to look at the moon, you should see sharp details in the craters, but it will at times seem to shimmer or boil - this is seeing or scope currents and is normal - but other than that you should be able to trace nice sharp craters in the moon's surface all over
Make sure to collimate and then play with focus a good bit.

Kenneth Naim

  • Active Astronomer
  • ***
  • Posts: 119
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Quick Q after first time out
« Reply #2 on: January 01, 2018, 03:14:05 AM »
Some simple iPhone type videos of jupiter through an 8" scope to give you a sense of what you should be seeing:

https://www.youtube....h?v=ProOhknvS3o
https://www.youtube....h?v=a8yBv5phuys

unoutdethea

  • Active Astronomer
  • ***
  • Posts: 126
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Quick Q after first time out
« Reply #3 on: January 04, 2018, 04:51:46 AM »
What time of night was it on what day? Maybe Jupiter was particular close to another bright star.

Alternatively, your experience does sound a lot like looking at Venus

James Przystup

  • Active Astronomer
  • ***
  • Posts: 132
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Quick Q after first time out
« Reply #4 on: January 04, 2018, 08:24:46 AM »
Quote
You don't need a Barlow you need to collimate your scope. If the moon is fuzzy because your scope isn't collimated (not due to bad focus or seeing which is also possible) then Jupiter, if you found it and are not looking at a bright star like Sirius, is going to look like absolute rubbish aka a blob of white like you saw.

If one is collimating a Newtonian with a laser, the primary should be adjusted using the Barlowed Laser..

As far as Jupiter.. the 9mm eyepiece should show the moons and the disk but...

Jupiter doesn't rise until about 9pm. To get a half decent view, it needs to be at least 30 degrees above the horizon, that means it needs to be close to midnight.. A good possibility is that Jupiter was low on the horizon..

Jon

micnoasolos

  • Active Astronomer
  • ***
  • Posts: 136
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Quick Q after first time out
« Reply #5 on: January 04, 2018, 05:12:10 PM »
According to the specs, the XT8 comes with a collimation cap. This one came with my Orion 6" f/5 Newtonian...

Place the cap in place of the eyepiece, and point the telescope at a bright light source, at the sunlit sky during the day, or at a lamp or ceiling fixture indoors. If you have a digital camera with a display screen, you can place it over the pinhole of the collimation cap and zoom up close to what I call the "scene", and as reflected within the secondary mirror directly beneath the focusser. If the telescope is well-collimated, then this is how the scene should appear ...

For additional information...

http://www.astro-bab...ation guide.htm
http://www.cloudynig...-ota/?p=6998508

Daniel Johnson

  • Active Astronomer
  • ***
  • Posts: 128
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Quick Q after first time out
« Reply #6 on: January 08, 2018, 05:08:09 AM »
You were not looking at Jupiter. I have not had luck with phone apps either, always pointed a good distance away from where it really is. I recommend Stellarium for your laptop or computer. It's free and will be a big help. When you see Jupiter there will be no question what you are seeing.

Bobby Cruz

  • Active Astronomer
  • ***
  • Posts: 125
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Quick Q after first time out
« Reply #7 on: January 08, 2018, 12:31:14 PM »
Welcome fellow newbie. I have a 8" Zhumell dob. For Jupiter I didn't expect much, maybe 3-4 of Galilean moons, 3 if one was behind or in shadow of Jupiter. Someone else can correct me if moons don't often hide. To my inexperienced eye using a 26 mm EP (Eye Piece) could see numerous bands. Did you give eyes time to dark adapt and continue to protect your night vision? I only wanted to comment because we're newbies, the more experienced will see things our 'newbie' eyes will miss. I don't know if eyes not dark adapted would Jupiter become white disc?
Thanks

loasandkosem

  • Active Astronomer
  • ***
  • Posts: 137
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Quick Q after first time out
« Reply #8 on: January 08, 2018, 08:07:29 PM »
Quote
Welcome fellow newbie. I have a 8" Zhumell dob. For Jupiter I didn't expect much, maybe 3-4 of Galilean moons, 3 if one was behind or in shadow of Jupiter. Someone else can correct me if moons don't often hide. To my inexperienced eye using a 26 mm EP (Eye Piece) could see numerous bands. Did you give eyes time to dark adapt and continue to protect your night vision? I only wanted to comment because we're newbies, the more experienced will see things our 'newbie' eyes will miss. I don't know if eyes not dark adapted would Jupiter become white disc?
Thanks


I am a newbie as well, but from experience I can say that dark adaption does NOT affect your views of Jupiter to any great degree. Under GOOD seeing conditions, with my new to me 4" refractor using the 25mm stock eyepiece, I can see the 4 Galilean moons and 2 equatorial bands. With my 7mm X-cel I get a bigger Jupiter and multiple bands on the planet... under bad seeing, which I had a few nights ago when I looked, Jupiter was a pile a mush, to the point, had I not known better, I would have thought something was wrong in the optical train. Last night the seeing was very good and Jupiter looked mighty fine! And I went straight from inside a well lit house to my back porch where my scope was set up.SEEING CONDITIONS MATTER! Dark adaption on bright planets, not nearly so much.

Of course, YMMV...

Clear skies guys!

CB

Jeremy Fokused

  • Active Astronomer
  • ***
  • Posts: 120
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Quick Q after first time out
« Reply #9 on: January 10, 2018, 02:24:17 AM »
My two cents: One app that I use frequently and absolutely love is SkEye. It's an Android app and far exceeds other offerings such as Google Sky Map. Ensure that your GPS is activated on your phone and double check that your location is accurate and you'll be amazed at what the app offers. I also use Night Sky Tools, which offers numerous neat functions such as reference information for the Messier, NGC/IC, Caldwell and SIMBAD catalogs.If you find a target that you'd like to pursue then it will offer viewing information based on your location. Both of the apps are free and feature-rich yet approachable by even the less technologically inclined. Clear skies to you!

Cesar Rojas

  • Active Astronomer
  • ***
  • Posts: 128
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Quick Q after first time out
« Reply #10 on: January 10, 2018, 04:57:25 AM »
If you live in the Denver area, PM me and I will help you collimate the scope. I also encourage you to join a local astronomy club...you'd be surprised at the knowledge level and willingness to help others clubs provide....

bumabbefat

  • Active Astronomer
  • ***
  • Posts: 116
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Quick Q after first time out
« Reply #11 on: January 10, 2018, 07:00:45 AM »
In addition to what everyone else has said about collimating your scope and figuring out if you are actually looking at Jupiter or what, you need to let your scope equilibrate with the outside temperature before you start collimating or seriously looking at things. If the scope is cooling down, the optical path and thus the focus will be changing slightly as things contract and move a bit. For an 8" dobsonian, this cooling down might take anywhere from 30 minutes to over an hour. When I'm going to observe from my backyard, I put the scope out when I get home from work and then it's cooled down after dinner.