Viewing jupiter

[gt87]

Hello I have had a telescope now for about 6 months I am using a Nexstar 127 Slt with a Baader Hyperion zoom lens. I have been trying to view jupiter in the mornings before the sun rises as it is now getting higher in the sky before sunrise, I can easily see its 4 moons which are sharp and look like small stars, however Jupiter appears as a glowing white, ball I have checked the collumation and it appears to be good. I have tried using filters with no affect. what I find particularly interesting is the fact that if I put jupiter slightly out of focus I can see jupiter split into two, the left is a glowing white ball and the right I can see the bands and the red spot but only when out of focus. when I can see the bands the best way to describe it is like it has a large lens flare. I have tried it with different lens, without the mirror diagonal and cooling the scope for 1 hour before viewing and under what I would consider good viewing conditions. I have also tried looking at Venus and seem to be getting the same (it never seems in focus) I can barley make out the phase

 any ideas what this could be my first thoughts where collumation but I can see the moons of jupiter sharply. but I don't know if this is because they aren't as bright as Venus or Jupiter.

Kind regards 

[happy-kat]

Can you see our Moon with sharp focus at times?

[gt87]

Yes I can see it sharply but with highest magnification it becomes blurred I have attached a typical image of the moon with 20 mm lens

moon 3.bmp

[dweller25]

Have you fully cooled your scope before viewing ?

 

[gt87]

Ive left it out for 1 hour at the longest but this had no obvious effect but that was when the sun was just rising. now I've been leaving it out for 20 minutes but still looks the same just a glowing ball 

[happy-kat]

Atmosphere and seeing can play a huge part on sharpness, one day the Moon may just never resolve sharply and another as you watch it it will drift in and out of focus.

Have you never seen the Moon drift into sharpness?

Welcome to the forum.

[happy-kat]

To image the Moon generally a short video is used as then an image is made from lots of frames using something like registax . It's hard to get lucky that there was no turbulence as a single shot is taken.

[gt87]

The moon tends to stay sharp using my 20 mm lens but if I go to 10mm it I can see variations in sharpness like a heat distortion. I have managed to correct this to an extent using registax. but would this have a influence on viewing an object like jupiter ? I have taken a video of jupiter in the morning but it looks very distorted at that magnification  (using a neximage 5) 

[gt87]

This was my first attempt at videoing jupiter with a neximage 5 connected to my scope. the view through the scope isn't much different 

jupiter.wmv

[newbie alert]

Looks like too much gain (basically too bright) ..is there that setting on the nextstar?.. i take it your using i cap software..

[happy-kat]

When switching eyepeices and/or when switching to your imaging camera you will need to adjust focus again. When viewing the Moon and Jupiter I have seen a boiling image just from atomospheric turbulence and have to sit and continue viewing to glimpse brief periods of clarity.

 

[gt87]

Yeah I haven't figured out how to adjust that yet, contrast brightness, gain in icap any ideas ? the image coming from the scope looks poor anyway just a white ball 

[gt87]

Thanks happy kat 

Would it be reasonable see bands on jupiter rather than just a bright white ball. I'm still not sure why I can see more detail on jupiter out of focus. it's like the image has a lens flare covering it and when it goes out of focus it flares out to the left leaving two images the right I can just make out the bands. here is a image I made which looks like what I can see

[newbie alert]

If you open up the tab and unclick the auto settinfs you can adjust the sliders on exposure and gain...also to keep you file size down you can select the ROI(region of interest) and just box it to the size you want..

[happy-kat]

Just had a thought, are yopu getting dew form on the lens. If you are then perhaps make a dew shield from a camping mat or similar and see if that helps.

[happy-kat]

What about a star colimation test. Using your 20mm to start with, what do the concentric rings look like when you go both sides of focus.

[gt87]

Thanks newbie alert I got the gain and exposure adjustments working. thanks so much. I

 

[gt87]

I only get concentric rings on one side of focus is that normal?

[happy-kat]

Do you observe close to very bright lights, or a very near by street light?

[gt87]

I've got a dew shield made from a camping mat. there is one very bright Street light but it's normally turned off just before sunrise when I try to view jupiter. I did a star test and noticed rings one side only. I did the same test using a far neighbours Xmas lights while it's cloudy (I wasn't looking at his wife honestly it was purely scientific) ? still concentric rings on one side and blur on the other. 

[happy-kat]

This is beyond my limited knowledge, hopefully someone will see this and be able to offer help.

Keep plugging :-)

[happy-kat]

I wonder if you have a local club you could take it along to and see what suggestions you get there.

[Stu]

This is an example of an iPhone image, admittedly through a top end frac, but you should certainly be able to see some detail if you get the exposure under control.

Do try and post a star test image, one in focus and then either side of focus, that might help us.

[Alan64]

"I have tried using filters with no affect."

Have you tried a variable polariser?  Such dims down the brightness of an object in order for details to be seen, from 40% to only 2%.  Jupiter is rather bright...

http://www.rothervalleyoptics.co.uk/antares-variable-polarising-filter-125.html

This is an afocal snapshot of Jupiter taken through my 150mm f/5 Newtonian...

A 127mm Maksutov, with a secondary smaller than that of my 150mm f/5, gathers a considerable amount of light.

Incidentally, the flares coming off of the planet are the result of the Newtonian's four spider-vanes.

I had the same issue in not being able to see any detail; only a bright, featureless orb.  I then popped in the variable polariser, dimmed the flares out, and lo and behold, the features appeared; even the whorls and festoons within the equatorial region during a few seconds of excellent seeing.

I'd give that a go, if you haven't already. 

In so far as the out-of-focus patterns during a star-test, I've seen that many times with all of my telescopes, and due to the atmosphere; the seeing.

[happy-kat]

Did you buy your telescope new?

Some might be interesting links.

defraction link

read about someone else with an issue, interesting even if might be unrelated

another link here might be interesting to read