# Presentation: 604663

## DES Sky Camera (Cloud Camera)

- (FNAL)
- Cloud Camera Review
- 3 January 2008

## SkyCam Purpose

-    An All-Sky Camera is needed in order to:

- Provide real-time estimates of the sky conditions for survey strategy
- E.g.: “Should the next target be a photometric calibration field, a science target, or something else?”
- Provide a measure of the photometric quality of an image
- E.g.: “This image was obtained under such-and-such conditions; is it good enough to be used for photometric calibrations?”
- Detect even light cirrus for the above purposes under a full range of moon phases (no moon to full moon)

## SkyCam Functional Overview

-    The Sky Camera system should*:

- Image the full sky at a wavelength of ~10 microns once every 30 seconds throughout the course of nightly operations of the  Blanco 4.0m telescope.
- Process the images in real-time.
- Output in real-time a GIF version of the processed image to a webpage.
- Output in real-time a quantitative diagnostic indicating the cloudiness of the sky (e.g., the rms of the pixel values from the most recent processed image) to a web-accessible graph and to an archival database.
- Create and animation based upon the processed images from the past hour to detect cloud movement, and output this animation to a webpage.
- Create an animation based upon the full night’s processed images at the end of each night.
- Archive the raw and processed FITS images, processed GIF files, and the full-night animation to a web-accessible directory.

- *Based upon the functionality of the APO 10 micron all-sky camera, which, in its current incarnation has been operating successfully since 2001.

## APO 10 micron All-Sky Camera Output

- Clear

- Cloudy

## Proposed SkyCam DB Inputs

- SkyCam table in DB:
-  Date & Time Stamp (UT/TAI)
-  mean sky brightness
-  std dev of sky brightness
-  “photometricity” flag (0/1)
-    (or threshold value of the std dev
-    of sky brightness considered
-    photometric)
-  name of associated SkyCam FITS
-   images (raw and processed)

## APO 10 micron All-Sky Camera Hardware

- Design of the current APO 10 micron
- all-sky camera, commissioned in 2001

- A photograph of the APO 10 micron
- all-sky camera

- Credit:  APO

- Credit:  APO

## SkyCam Disk Space Needs(Assuming APO Design)

- Image size:  320 pixels x 240 pixels
- 16-bit FITS images
- 150KB per FITS image
- 1 FITS image every 30 seconds
- 12 hours per night operation
- 1440 FITS images per night
- 1440 FITS images/night x 150KB / FITS image = 211MB / night
- Saving all images in GIF and animated GIF format as well as FITS format could conceivably triple the diskspace requirements
- Ancillary files (like nightly QA plots and logs) may only add an additional 1 MB per night or so to the archive
- 3 x 211MB / night ~ 630 MB / night
- Annual storage requirements ~ 630 MB /night x 365 nights ~ 225 GB

## APO Design Cost Estimate*(29 December 2007)

| Raytheon “Thermal Eye” 300D 10-micron camera | $8,000 |
| --- | --- |
| Video-to-optical fiber converters
(E.g., Opticomm MMV-110 Mini XMT, RCV pair) | 2x$275 |
| Frame grabber (E.g., Hauppauge WinTV 191) | $100 |
| Pentium Desktop with 1-GB RAM and 250 GB HD | $3,000 |
| External 250 GB HD (backup) | $250 |
| 18-inch-diameter hyperbolic mirror (machined aluminum) | $3000 |
| Camera support structure and enclosure
(Base plate, canopy, mount plate/strut assembly) | $2000 |
| Paint assembly titanium white epoxy
 | $400 |
| Polish the aluminum mirror | 1 FTE Day |
| TOTAL | $17,300
+ 1 FTE Day |

- *Based upon information from the APO IRSC documentation page,  _[http://irsc.apo.nmsu.edu/irsc_doc/](http://irsc.apo.nmsu.edu/irsc_doc/)_, and from e-discussions with Mike Carr.

## SkyCam Timeline

| Finalize design and start obtaining quotes for materials | Mar 1, 2008 |
| --- | --- |
| Start constructing SkyCam and writing SkyCam software | Sep 1, 2008 |
| Start commissioning SkyCam and SkyCam software | Mar 1, 2009 |
| Complete commissioning SkyCam and SkyCam software | Sep 1, 2009 |
| Start DES | Sep 1, 2010 |

##  And that is how matters stood until October 2007...

-  And that is how matters stood until October 2007...

## IR All-Sky Camera

- IR camera with 180deg cone angle lens

- Visible Camera under dome

- IR Camera under hatch

- Black Body located inside hatch

-  Deployment in Chile around mid 2007
-  Comparison of IR images with SASCA images

- Slide Credit:  Jacques Sebag

- LSST Cloud Camera Design

## mid-IR Sky Transmission

- Slide Credit:  Jacques Sebag

- LSST Cloud Camera Design

## LSST Cloud Camera Design

- Slide Credit:  Jacques Sebag

## Kitt Peak Run

- Mean and RMS over a window ~100x100 pixels centered on each filter4 image

- Slide Credit:  Jacques Sebag

- LSST Cloud Camera Design

## LSST Design Cost Estimate

- Estimate provided by Jacques Sebag (NOAO):
- System was purchased for $60K, which includes the unit itself, the software, and the computer.
- The price may have changed slightly along with small changes in the company’s design of the system.

- Credit:  Jacques Sebag

## APO vs. LSST Designs

_***APO Design***_
_**Pros:**_
- Robust
- in use at APO for several years
- Inexpensive
- APO designs and software freely available
- Materials cost < $20K
_**Cons: **_
- 1st generation 10-micron all-sky camera
- probably outdated by 2010
- APO itself may have upgraded by then
- One of a kind camera at CTIO
- less maintainability
- less redundancy
- semi-customized (not purely “off-the-shelf”
- Not flux calibrated

_***LSST Design***_
_**Pros:**_
- High level of maintainability
- duplicate of camera to be sited on Cerro Pachon for SOAR and LSST
- Partial redundancy
- Although not ideal, if one of the two cameras fails, one can use the outputs from the camera on the other mountain as a temporary “stop-gap” solution
- Several filters + optical all-sky camera  more sky diagnostics
- “Blackbody on Board”  flux calibration
- More-or-less “off-the-shelf”
_**Cons: **_
- More expensive (~$60K)
- Cost sharing with CTIO can mitigate the expense to DECam.
- Sky diagnostics still under development
- So far, limited use under field conditions