Alan HolmesFounder and President

New products at SBIG

SBIG is Now Part Of Aplegen

• New Management intends to:– increase astronomical product research

and development– adds new cameras with features suited

to life sciences applications such as:• Gel Imaging• Fluorescence microscopy

• New CEO is Ron Bissinger, known for amateur exoplanet measurements

Past SBIG Cameras over the last 23 years

• ST-4 (my baby)• ST-6• ST-5/ 237/ PixCel 237• ST-7/ 8/ 9/ 10/ 2000 line• STL-11000/ 6303/ 1001 line• STX-16803/ 6303• ST-402/ 1603/ 3200• SG-4

New Camera Models in Last Year

• ST-I• ST-8300 and STF-8300• STX-6303

ST-I is a new Guider/Planet Camera

ST-I Features

• 640 x 480 pixel interline CCD• 7.4 micron square pixels• Exposures as short as 1 millisecond• 16 bit A/D converter• 10 electrons read noise• powered off USB port• Shutter for automatic dark frames• Fits in 1.25 inch eyepiece tube

ST-I Comes with a Case and Software

A Guiding package is Available that is all Most Users Need

Planetary Imaging is also Possible

(Not the best but it’s mine!)

ST-8300 is our most Popular Camera

• Features– 8.3 million pixels – 16 bit A/D– 38 degree C cooling– 5.4x5.4 micron pixels - good for refractors– EXCELLENT low dark current– Just went on sale at a great price - $1795 US

5 (and 8) Position Filter Wheels are Available

The ST-8300 is capable of Great Images!

Peter Clausen

Peter Clausen

New STF-8300 Provides Faster Readout

10 Megapixels / Second Full Frame Image Buffer Readout and Download Simultaneously Download Full Frame < 1 sec. User Rechargeable Desiccant Plug Internal Image Processing – Raw or Processed

Even-illumination (Photometric) Shutter 32-bit and 64- bit drivers for all Windows O/S Equinox Image and Equinox Pro for Mac Base Price $2495 US

STX-16803 is our largest CCD Camera

•4096x4096 pixels

•9 micron pixels

•Excellent Cooling

Martin Pugh

STX Images -Johannes Schedler - Austria

M97-Owl Nebula (too far north for Santiago!)

More STX Images from Johannes

NGC 5033

New STX-6303 is Excellent for Narrow Band Imaging and Faint Objects

Adriana Sherman, Guatemala

New Accessory Products at SBIG

• Differential Guiding • ST-8300 Off Axis Guider

Differential Guiding Solves a Difficult Problem

• When guiding at long focal lengths with a guide scope, the scope-to-scope alignment drifts due to:– Gravity direction changes– Thermal effects– mirror flop– mechanical shifts

• Differential guiding eliminates all of these

SBIG’s New Technique: Differential Guiding *

• An artificial star is created near the imaging CCD focal plane

• Beam of light from artificial star exits telescope

• Beam is retro-reflected into guide scope• Guide scope views both artificial star and

background star• Separation of artificial and real stars is

maintained by guiding* Patented

Differential Guiding Diagram

Main Scope

Guide Scope

LED

Guide Camera

Retro-Reflector

Imaging

Camera

Guiding is Adjusted to Maintain X and Y Offsets Constant

Guide Star

Artificial Star

X

Y

Retroreflector is Derived from Corner Cube and Dove Prism

Corner CubeDove Prism

Beam is exactly retro-reflected, and displaced to outside the telescope aperture. Retro-reflected angle is insensitive to small mechanical misalignments.

Testing was Performed in my Backyard

A Celestron Edge 14 was used for the Test

Retroreflector Assembly and Guide Scope (Hutech 50 mm F/5)

ST-8300 and Artificial Star Generator

Conventionally Guided Image - 30 minutes

Differential Guided Image - 3 x 30 Minutes - no Shifts!

It Works Great! (ST-8300C Data Added)

New Off-Axis Guider for ST-8300

Guider Ray Trace Diagram

• Allows guiding in front of the filters• Also provides focal reduction for 2X

more area

Imager CCD ST-I

CCD

It uses an ST-I and Mounts to Filter Wheel

Low Profile – Adds only 19mm backfocus to camera and filter wheel (total about 58mm)

Built-in relay lenses and 0.7X reducer doubles the field of view of the ST-i

Guide camera can be mounted at 90 degrees x 4

St-I Guider Image at F/3.5! Stars are excellent for guiding

Celestron Edge 14 Image using OAG With ST-8300

Alan Holmes

OAG Makes Guiding Narrow Band Images Easy

Peter Clausen

-Astrophotography Hints-

Stray Light and Flat Fields

An Example of the Problem - An Expensive Refractor with an ST-8300

• Center to edge variation = 6%• There is NO vignetting in either image!• “Hot Spot” is caused by glints off internal cylindrical

surfaces near CCD Camera

Green Flat Field IR (940 nm) Flat Field

Measuring Stray Light: My “CCD View” Pinhole Camera

• Chamber window of ST-3200 replaced with a tiny lens

View of my office through a short 1.25 inch nosepiece

Looking into that High-End Refractor

Actual Aperture!

Bad Stuff!

Problem is glints off of “black” anodized surfaces. Total Stray Light is 8% Green, 18% IR

$5 Million Peso (!) RC Scope

Green - 13% Stray Light Near IR - 37% Stray Light

Aperture Edge

Why is this important? - Astronomical Features have very Low Contrast against the Sky Background

9% contrast

1% contrast

(Images are from a Dark Site)

Tony Hallas

Stray Light is also a Serious Problem for Photometry

Vignetting Stray Light Sum

Using a flat field to correct an image with stray light incorrectly increases brightness of stars near edge of field

(Looks like vignetting but it’s not)

A Collection of “Black” Objects Imaged at Near Infrared Wavelengths (940 nm)

White Business Card

Black Felt (79% reflectivity

Black Paper

Flat Black Paint

Flat Black Paint can solve this Problem - User Flat Field Images

STL-11K - Flat Field with Moonlite Focuser and ribbed draw tube

Flat field after painting draw tube with flat black paint

How to detect the problem yourself

• Point your telescope at a flat field screen

• Put your eye at the point where you usually insert the camera

• Look into the tube

What can you do?

• Paint black anodized surfaces Flat Black– I prefer barbeque black - low temperature paints may use

dyes that are transparent beyond 700 nm• Add thin shim rings to work as knife edges baffles• Do NOT use incandescent bulbs for flat fields

– Use white LEDS instead – Better, but still not perfect

• Sky flats may help - matches spectrum better for LRGB imaging• Use flat field for each color if doing RGB images• Photometrists should map response by moving stars around in

field to detect problem

It is Worth the Effort!

Tony Hallas

Particularly with Huge Mosaics (Rogelio Bernal Andreo - 19 APODs!)