Wide FOV w/Lodestar

[HiloDon]

Hi All,

Thought I would share my last night's capture of Eta Carinae. I have always wanted to see it and finally got a good chance last night albeit pretty late. I had to deal with some trees and clouds, but finally got a window about 3:30 am. I used the NB Ha filter and 50 mm finder scope with about a 180mm FL. Could use a bit more FOV. I have an Orion 50mm mini guide scope coming that has a 162mm FL and I still want to try some of my Nikon lenses. But I was happy to get this.

Don

[AstroEd]

Don great shots again, Is the finder basically a 50mm doublet? My gear is all in but waiting on a smaller counter weight and clear skies, had first light on my new 80mm scope with a Mallincam at a friends house. Soon as we have some clear skies I will get first light with it and my color Lodestar x2. Keep the great shots coming they are an inspiration.

[HiloDon]

Thanks, Ed. The finder is a simple doublet achromat. The FL is about 180mm. When you get so short and fast, the field curvature becomes an issue even with the small sensor. The depth of field is not large enough to focus the entire image. You can see what looks like coma at the edges, but it's field curvature. It doesn't seem to affect the object image, so I'm still pretty happy using it as a wide FOV NRTV system. The NB Ha filter is necessary to cut down the star bloat. I tried the color Lodestar with a UV/IR cut filter and the image looked like polka dots. When I use my 80mm ST at native 400mm FL, there is no apparent field curvature problem. Here's a couple of shots I took with the Orion 80mm ST.

[Paul81]

Great stuff Don, I really like Eta Carinae - another enviable aspect of your location is dark skies and also a good portion of the southern skies too!

The 80mm works a treat too, the HH, Flame and M42 look amazing. I think you have hit the display settings spot on for M42 as there its lots of nice faint detail. I am hoping the new scaling code will really help objects like this with really bright cores and faint outer detail.

[HiloDon]

Thanks for all of your kind words, Paul. I wouldn't be able to do any of this without your efforts on LL. You have given us a simple easy to use method of utilizing a great camera for EAA. I look forward to v0.11.

Don

[arkosg]

Hi all,

I was inspired by Don's awesome wide field shots and thought I'd try to see if I could do something along the same lines.

I'm using the 50 mm finder on our CPC 800 HD (alt-az) with the eyepiece end removed as per Don's photos, and with a Baader 

Clicklock with 1.25" adapter into which I inserted the Lodestar.  Focus was a bit hit and miss, but I found I was able to get 

there with some persistence (a nice helical focuser would probably work great for this and be less work).  My viewing location 

is pretty urban (though there are no lights shining directly onto my observing site), and there was a (just past) First Quarter Moon.

Don: you must have tremendous skies!  I'm limited to about 20-30 s max, rather than the 45 s Don was using.  I'm also using

the Lodestar X2C (colour), which is probably somewhat less sensitive than the Lodestar X2 (monochrome).  For brighter objects, 

I was pleased with what I was able to view.  I tried some of Don's targets (Rosette, Heart, Soul) and only got faint hints of the 

nebulosity from my site with the setup/exposures I was using; I've included my "image" of the Rosette as an example.

Enjoy,

- Greg A

PS.  My M42 image is mislabelled as M31 - apologies.  It was cold, and my brain must have been freezing up by that point.  ; - )

[shirva]

Nice images greg..davy

[HiloDon]

Hi Greg,

Great results! I don't see much field curvature problems like I have in mine. Are all of these single 20-30s exposures? Did you try any stacking? Did you follow Paul's instructions on increasing the gamma and using the contrast setting to broaden the histogram? A little more exposure or brightening on the dim objects would make a big difference. Nice job. Pleiades is spectacular.

Don

[Martin Meredith]

Great work! Its good to see these objects in a new context. At this FOV M37 looks like a glob! Did you use any filters for these shots?

It will be interesting to see which finders perform best. I'm tempted to give this a try with the one that came with my Quattro...

Martin

[arkosg]

Hi guys,

Thanks for the feedback!

No filters for these shots; all are stacks of 15-25 s exposures (I can sometimes get away with 30 ish seconds, but usually start to see obvious jitter/trailing, depending on where in the sky I'm looking).

Don - I've been trying Paul's suggestions, with mixed results. I find the sky background tends to be fairly bright and it makes contrast with faint objects a challenge, regardless of how I tease the settings on LL. I do see some improvement if I increase the exposure length and stack, but my alt-az mount just won't allow me to go as long as I'd probably need to.

I'm tempted to buy an equatorial mount and a nice refractor to compliment this current setup.... I was surprised how nice some of the finder scope results were, given the limitations.

Cheers,

Greg A

[Paul81]

I am really liking these finder scope shots.

The Altair Astro 60mm finder (F3.75) might be interesting to try - it seems built for a finder and also a finder-guider so I would have thought it would be ideal for this type of work. Not sure if it has the ability to accept a 1.25" filter - it seems this is quite necessary to cut down light pollution.

The finder on my scope is rubbish so I might kill two birds with one stone!

[arkosg]

If we're not careful, we will create a new hardware niche with all these finder shots!

[HiloDon]

Right, Greg. I can see it now. High end ed 2" refractors with field flatteners and dual speed focusers. Cost? About a grand.

Don

[arkosg]

Oh no, Don.... much more upscale!

I'm thinking a "Petzval, 4 element 2", with flat field & feather touch focuser; carbon fiber" bundled with a Lodestar (X2 or X2C, your choice).

If you have to ask about the price, you can't afford it.  

People will be trading in those big TMB and AP refractors... not.

- Greg A

[HiloDon]

I forgot about the carbon fiber tube! That should really help cut down the weight.

Don