M42 from Abbey Wood.

[Mac]

Well i finally got round to charging the batteries and fixing the dew heater, and set about taking some photos last night, Heres the result.

I did take quite a few, but as i said in an earlier post the LX200 is subject to vibrations, even though it was dead calm at 01:00 last night.

M42 
LX200 F6.3 focal reducer.
Nikon D100 200ASA. shot in RAW.
90 seconds, unguided
LPR Filter
No flats
One dark.
Processed in photoshop.
cropped to 800 * 533

[JohnP]

Hi Mac,

Well done is that a single exposure or multiple stack - you have nice detail showing in the Trapezium region.

John

[Mike]

What kind of vibrations are you referring to Mac?

[Mac]

Its just a single shot.

i did have a few that could be stacked, but registax wasn't playing ball, so i just went for the best one.

As for the vibrations

The vibrations are from the whole scope, being buffeted by the wind, even the mirror from the camera causes some vibration,
although it is cut down by mirror lock,

You only have to touch the telescope and the image jumps around by a huge amount, so unless its dead calm
imaging is sort of a no no.

The only way to remove the vibrations would be to damp the forks down but that would then make the scope

to heavy to even lift, at the moment its quite a weight .

I dont thinkits the tripod as thats quite firm and sturdy,

Plus the fact its centre of gravity is also quite high,
thats why i was thinking of moving the OTA and setting it on something like an EQ6.

[JohnP]

Mac,

Use Deep Sky Stacker for stacking DSLR raws - it is so much easy than Registax - believe me..... It's free as well!!!

http://deepskystacker.free.fr/english/index.html

John

[MarkS]

I like the picture Mac.  There's some evidence of circular smear which indicates your mount was not quite polar aligned.

Stack a few images like that together and it would be quite impressive.  As John says, Deep Sky Stacker is dead easy to use. 

[Ian]

Looks good to me mate.

I'm not sure that the circular smearing is polar alignment issues, that'll cause linear trailing. Circular trails are more likely to be caused by the vibrations Mac has complained about...

[MarkS]

Mac,

Was the scope mounted alt-az on the tripod or did you have it on the wedge?

[Mac]

I had it on the wedge.

and i did spend about 45 mins getting it polar aligned, i know it was off ever so slightly,
because after an hour, Aldebron was just out of the field of view in a 12mm eyepiece,

(Dinner) so i had to leave it tracking.

so i was happy with that as i am limited to about 3 mins, due to the noise on my cameras ccd.

I've also just checked my M45 as well,

this was with the camera mounted on top of the telescope

and was 300m F13



Dosent seem to be any obvious field rotation, this was a single 180s.

It might be the effect of the 6.3 field flattner.

The stars top right, bottom right and bottom left would show the greatest rotation,

but they dont appear to show any rotation,


I'll have to take a few more and compare the difference with and without the 6.3, just to see if it is the

optics that is introducing the rotation.

[The Thing]

Hi Mac,

I have an 8" LX90 on a Meade wedge. After alignment I lock down the wedge to the tripod with three extra bolts in the elongated holes provided (loo seat bolts as they are the correct thread). These stop the wedge flexing as much as it would otherwise do with the single central fixing point.

I also put sorbothane blocks under the tripod legs. The sorbothane blocks used to be under my LP turntable a while back and do a great job of killing the vibration caused by my Minolta Dynax 7 mirror going up before the exposure starts and damping down any other vibrations. I can thoroughly recommend DeepSkyStacker for RAW images. 

When I am using my Phillips SPC900NC webcam and a 2x barlow any movement shows up on the laptop screen. This combination of measures stops planets moving around the frame too much quite effectively so that Registax has no trouble aligning frames. Before I used the blocks it was hopeless.

I am toying with the idea of filling the cavities in the sides of the wedge with epoxy or something to strengthen it further.

Hope this helps,

Duncan

[Mac]

I had a chat to the guys at telescope house, re the strange vibration problems, that i was having,

The answer that they came up with was the 3D rail for balancing the scope.

They said that unless I've got a serious amount of kit hanging off the end, ccd, filter wheel, barlo, ect ect.

Then try to avoid using the weights, as this would bring the centre of gravity much much higher up the scope,

This would / could induce the vibrations that i've been having.

They also said that the gears on the lx200 should be able to cope without a problem with the d100 slung on the back.

As for the vibration pads, I generally have the tripod sitting on paving slabs on the garden, so they are quite firm.

Also i tend not to walk around whilst imaging. but i have tried and it dosent seem to affect the photos.

Its just these strange vibrations.

The only problem now is actually getting a clear night to try these things again and see whats happening.

[Fay]

You did well, Mac.
I hope there is not a sudden escalation of loose loo seats, in the area, after Duncan's admission!!!!!!!

Fay