Merlin66

Louise,

Think of the reflective slit plate as a on- axis guider or a star diagonal. All it does is reflect the FOV at the slit position.

The transfer lens - depending on the spacing between the slit plate and the final guide image then acts as a reducer - giving a slightly larger FOV in the camera. As far as I can see the reduction is x0.72.

The actual guide FOV will depend on the area of the slit plate visible to the guider, the reduction factor and the guide camera chip size.

In my case the slit plate has a front cover, with an aperture of 8 x 6 mm, centred on the slit gap. This effectively limits the actual area of the sky visible ( the camera FOV is much larger, but obviously blocked by the cover plate!)

In my C11 @ f10 I get 9.8 x 7.4 arc min coverage.

I can easily put a target star close to centre in the 60/220 eFinder and find the same field in the spectrograph guider. If you use PHD2 you can set up the virtual slit and nudge the target into/onto the slit gap.

Much easier than you think.

I agree with John. Trying slumping a couple of 12" disks, one was about 6mm thick the other 10mm (?) Used the services of the local ceramic group and their Kiln.

Making a "proper" mould to slump into proved difficult, temperature control/ annnnealling became a PITA!

Supporting the disks for grinding - sand bags/ air bags/ various disks of carpet didn't work for me.

An alternative was to vacuum distort a thin blank (which already had a "reasonable" finish) - supported on an edge O ring within a closed cell and hand vacuum pump connected to the rear. Yes, I think it would have eventually worked, getting around f10.

Don't even think of stretching a Mylar mirror and vacuum!!!!!

They are the work of the Devil!

Sounds like the usual “death rattle” I have on my NEQ6PRO.

The gears/ belts don’t disconnect, just the stepper motors interacting with the gear train.

You get used to it after a while........

Check out:

I don't think there is anything to get worried about....

You've got yourself a great performing telescope. Enjoy it!

The small dabs of visible glue are a non event, I think these are there to lock the retaining ring, they have no impact whatsoever on the scope or it's performance.

(I have and use three ED80's - love them all!)

What plate solver did you use?

I use a C11 @f10 on the NEQ6pro with EQMod.

I also have a 60/ 220 eFinder (using a DMK51). I can plate solve the eFinder field to confirm centring of the target . I only do spectroscopy.

Question:

Are you using EQMod or the Synscan hand controller??

John,

I've used the HEQ5 and NEQ6pro for many years, and to prevent a low voltage condition I added a 120W car converter - 12V to 15V (Jaycar/ Maplin etc ).

Never had an issue/ concern,

Rusted,

Doesn't work like that.... The typical "blocking filter" is actually made up of at least two elements.

There are two factors to consider

1. The reduction in heat/ energy load

2. The "sort filter" required to suppress all the etalon "bands" other than the one at Ha

The ERF combo etc will look after #1 but does nothing for #2

A sort filter requires a very narrow bandwidth (typically <10A) and be set/ tuned to the Ha CWL (central wavelength)

No,  it should assume you're at the "Home" position - pointed to the pole counterweight down.

Set the scope to this position - unpark and you should be good to go.

OK.

A bright star like Betelgeuse will show multiple images in the guider.  The incoming light is reflected from the front surface of the glass slit plate (about 4%), then reflected from the chrome slit surface, ( about 90%) (1.5mm behind the front surface), then internally reflected from the rear of the front surface, reflected by the chrome etc etc. Giving fainter "companion stars". This is normal with a glass reflective slit plate. Don't reverse it!.

The guide image shows astigmatism - the first images are distorted vertically.....the last images distorted horizontally. I'd put this down to mis-alignment of the guide optics. Not originating in your scope.....

The exposure/ settings of the guide image could possibly be reduced to minimise the bloat of the star image....

Looking at the spectral image - I'd say that the telescope focus was not exactly on the slit gap, hence the double line - I think that's your secondary mirror out of focus.  Refocus the telescope to get a narrow consistent band, then re-check your guide image, move the guide camera to get a tight image - the slit gap should also show a  clear and tight line.

The slant should be reasonably consistent across the spectrum - not a major issue, can be corrected in processing. Could be that the slit gap is not 100% parallel to the grating grooves.

Lucas, all in all, congratulations on your first light spectral image.

Onwards and Upwards.

Just a comment:

The latest version of the Synscan handcontroller (V5) is the only one with the USB port in the handcontroller.

All the previous versions (V2, V3 and V4) need to be connected using the "upgrade" SW cable with the DB9 serial plug at the computer end.

This usually (as very few, if any, current computers have a serial port), means adding a Serial > USB adaptor. I use the Keyspan adaptor.

Ahhh, OK.

The QHY5 has a 5.3 x 6.7 mm chip and the QHY5L II a 4.8 x 3.85 mm chip.

I also had to add a UV-IR filter to my guide cameras to improve the image.......

Louise,

Can't help with the printer problems....

I'm a little surprised to see the differences between your slit image and Paul's image....taken with the same QHY5 II camera.

I assume you both use the same focal length guider lens???

IMHO the circles are only cosmetic....

I’ve had and used the HEQ5 and the HEQ6 for over ten years and never used them.

Just use the software for general use.

Don,

My early smooth sided Meade "Super Plossls" , no rubber eyecap, are from the 1980's and stamped "Japan" on the black barrel.

The only other markings I've seen on other Meade SP's is Japan stamped on the chrome nosepiece, or China printed next to the description. I also have one ( 26mm rubber eyecap) with no markings!

I have a FULL modded Canon 1000D.

Yes, general daytime shots will come out with a pink cast.

Just take a photo of a white wall, it will be obvious.

To encourage and assist amateurs interested in making 3D printed spectrographs, we will prepare a web sub-group for them.
There are at least four concept designs being discussed - Paul's "LowSpec",
John's "Littrow", Christian's "UVEX" and Tony's "TRAGOS".

https://groups.io/g/astronomicalspectroscopy

You are more than welcome to visit and check out this exciting new development in amateur spectroscopy.

Louise,

Don't get too discouraged, you've come a long way....

remember what Kaler said "Pictures of stars show us what they look like - a spectrum reveals their souls"

Paul,

Your guide coverage looks very similar to mine - approx 8.6 mm x 6.8 mm.

Louise,

Spectroscopy 201.....moving from a transmission grating to a slit spectrograph....

Practise, practise, ......

When you start to record stellar spectra you'll find a new world of issues/ problems/ concerns etc etc etc.

The main thing at the moment is to get comfortable with acquisition and processing.....

Lucas,

Your results look very promising...well done!

With the reference lamp, change the exposure (depending on the wavelength area of interest) to ensure you don't saturate the lines - you can't easily use saturated lines for calibration....

Louise,

Re stars in slit gap....

You don't have an option to change target stars if your doing a specific observation. If there's a second star in the slit, as Lucas says you can just not select it for processing.

Louise,

It's normally much easier to orientate the slit horizontal or vertically in the guide camera, this makes it easier to judge which way to nudge stars onto the slit and maintains the RA and Dec direction for acquisition.

The slit gaps are 6mm long.

The guide FOV will be constrained by the size of the visible slit plate and the focal length of the scope being used. You can roughly estimate your guide FOV by measuring the slit length on the guide image to get a scale mm/pixel. In my case due to the slit cover plate I have an opening/ FOV of 8mm x 6mm. 

Using CCDCalc (see image) this gives 9.8 x 7.4 arc min coverage.

You want to achieve as good a focus as you can on the slit gap... then when positioning a target star it also should be in good focus (using the scope focuser).